Assessment of Oak Woodland Resources in BLM’s Eugene District Lane County, Oregon

Technical Note 406 June 2000

U.S. Department of the Interior Bureau of Land Management

December 1999

Assessment of Oak Woodland Resources in BLM’s Eugene District Lane County, Oregon

Technical Note 406

By:

David G. Chiller Research Biologist, Pacific Wildlife Research Inc.

David G. Vesely Senior Forest Ecologist, Pacific Wildlife Research Inc.

William I. Dean Wildlife Biologist, Bureau of Land Management, Eugene District

Eugene District Office 2890 Chad Drive Eugene, OR 97440-2226

June 2000 BLM/OR/WA/PL-00/052+6635

ABSTRACTABSTRACT

Because of the significant loss of oak (Quercus were delineated; and the topographic features, spp.) habitat and the subsequent increased value vegetation structure, and composition of the placed on oak woodlands for wildlife habitat, the sites were characterized. Current conditions preservation and restoration of native oak wood- were then compared with conditions docu- lands has become a priority for land man- mented in historical records. In addition, the agers and conservationists in the Western wildlife species most likely occurring on the United States. In 1998, reconnaissance sur- sites were identified. Literature from oak wood- veys were conducted on 13 oak woodland sites land studies was then reviewed to determine managed by the Bureau of Land Management’s whether certain management and restoration (BLM’s) Eugene District in Lane County, methods, such as eliminating conifer encroach- Oregon. The sites were classified as either ment and thinning closed-canopy stands, would meadow-type communities or woodland-type be effective in addressing conditions observed at communities; oak patches within the sites the BLM sites.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT



ACKNOWLEDGMENTSACKNOWLEDGMENTS

This work was part of a cooperative study, the development and implementation of this which involved the Oregon Department of project. We would also like to thank Rebecca Fish and Wildlife, The Nature Conservancy, Goggans, Douglas Gomez, Joan Hagar, David Oregon and Washington Natural Heritage Hibbs, Matt Hunter, Paula Larson, and Mike Program, and the Bureau of Land Management Reichenbach for their valuable contributions to (BLM), to investigate oak woodland habitats. an earlier draft of this report. Finally, we thank We would like to thank John Chatt, Carole Eric Campbell and BLM’s Oregon State Office Jorgensen, Lynn Larson, Cheshire Mayrsohn, for supporting the publication and distribution and Chris Melotti for providing significant logis- of this assessment, making it more available tical support and encouragement throughout to other resource managers.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

iii

TABLE OFTABLE OFCONTENTS CONTENTS

Abstract ...... i

Acknowledgments...... iii

Figures and Tables...... vii

Introduction...... 1 Oak Woodlands: Past and Present ...... 1 Assessment Objectives...... 2 Project Area...... 2

Methods...... 5 Site Selection...... 5 Site Classification...... 5 Oak Patch Delineation...... 5 Site Descriptions...... 6 Topography ...... 7 Patch Composition...... 7 Additional Descriptive Information...... 9 Oak Distribution Patterns ...... 10 Wildlife Habitat Associations...... 10 Wildlife Species...... 10 Habitat Components...... 11 Restoration and Management Literature Review...... 11

Results and Discussion ...... 13 Overview of BLM Sites...... 13 Physiography...... 13 Plant Community Composition and Structure ...... 13 Oak Growth and Regeneration...... 18 Site Descriptions...... 22 Anthony Creek ...... 22 Bates ...... 22 Cougar Mountain ...... 22

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

 Eagle’s Rest...... 23 Fox Hollow...... 23 Gilkey Creek...... 23 Kloster Mountain...... 24 Rattlesnake ...... 24 Sears Road...... 24 Seventy-Ninth...... 25 Weiss Road ...... 25 Wendling...... 25 Wills Road...... 26 Oak Distribution Patterns ...... 26 Regional Level...... 26 Patch Level ...... 27 Effects of Fire Suppression ...... 29 Wildlife Habitat Associations...... 29 Species that Use Oak Woodlands...... 29 Habitat Components of Oak Woodlands...... 32 Restoration and Management Literature Review...... 34 Conifer Encroachment...... 34 Thinning of Closed-Canopy Stands...... 35

Summary and Recommendations ...... 37 Vegetation Patterns ...... 37 Wildlife Habitat...... 41 Mast Production ...... 41 Vegetation...... 41 Cavities...... 43 Patch Size ...... 43 Oak Management Recommendations by Other Authors...... 44

Literature Cited...... 47

Appendix A...... 59 List of Wildlife Species Potentially Occurring in Habitats Found in the Surveyed Sites...... 60

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

vi FIGURESFIGURES AND AND TABLES TABLES

Figures Figure 1. Map of Lane County, Oregon, showing the distribution and location of the 13 survey sites...... 3 Figure 2a. Relationship between tree height and dbh for sampled oaks...... 20 Figure 2b. Relationship between tree age and height for sampled oaks ...... 20 Figure 2c. Relationship between tree age and dbh for sampled oaks ...... 20 Figure 2d. Relationship between growth rate and mean crown radius for sampled oaks. 20 Figure 3. Typical spatial pattern of oaks and conifers in meadow and woodland sites . 28

Tables

Table 1. List of surveyed sites, patch acronyms, and associated community types. . . . . 6 Table 2. Physical descriptors of individual patches including units and methods/instruments used ...... 7 Table 3. Variables and methods used to characterize canopy layers within patches. . . . 8 Table 4. Descriptive variables for tree composition of individual canopy layers ...... 8 Table 5. Summary of physical characteristics of surveyed patches...... 13 Table 6. Summary of the most abundant tree cohorts occurring in canopy layers in each surveyed patch...... 15 Table 7. Summary of selected oak size characteristics for each surveyed patch...... 16 Table 8. List of snags counts and characteristics for each surveyed patch...... 17 Table 9. Percent occurrence of the most dominant shrubs in the surveyed patches. . . 18 Table 10. Percent occurrence of nonnative plants observed in the surveyed patches. . . 18 Table 11. Growth and age information for sampled oak trees...... 19 Table 12. Estimates of oak regeneration abundance in the surveyed patches...... 21 Table 13. Historical vegetation classifications for the surveyed sites...... 39 Table 14. Classification of surveyed sites based on site characteristics, degree of conifer competition, and possible management actions...... 40 Table 15. Estimated annual acorn yields for the surveyed patches...... 42

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vii

INTRODUCTIONINTRODUCTION

tree harvesting, and urban development also have Oak Woodlands: Past led to widespread changes in Willamette Valley and Present landscapes (Towle 1982). In addition, the estab- lishment of introduced plant species within oak The preservation and restoration of native woodlands and grasslands (Habeck 1961) has oak (Quercus spp.) woodlands has recently greatly altered plant community composition. become an important priority for land man- agers and conservationists in the western Despite these changes, existing oak environ- United States. This effort has been driven by ments continue to represent important and a growing recognition of the significant loss of unique habitat for numerous wildlife species. oak habitat and the subsequent “increased In California, over 300 vertebrate species use value placed on oak woodlands within the past oak-dominated woodlands for various purpos- 20 years, for esthetics, wildlife habitat, water- es (Block et al. 1990). Oak woodlands in the shed functioning, outdoor recreation” and Willamette Valley have a greater avian species other qualities (Pillsbury et al. 1997). diversity than Douglas-fir and western hemlock (Tsuga heterophylla) habitats (Anderson 1972) In western Oregon, oak woodlands in the and provide a higher density of cavity resources lowlands and neighboring foothills of (Gumtow-Farrior 1991). Not only do oaks pro- the Willamette Valley have been heavily vide resources for numerous species of wildlife influenced by human activity for centuries that are known to use acorns (Christisen and (Johannessen et al. 1971). Extensive annual Korschgen 1955), but the leaves and twigs of fires set by Native Americans prior to immi- oak trees and associated plants provide resources gration of settlers in the 1840’s, maintained for an undetermined number of additional ver- open oak savannas and prairies and excluded tebrate and invertebrate species (Verner 1980; tree species not adapted to frequent fire Pavlik et al. 1991; Keator 1998). Conservation, regimes (Cole 1977; Franklin and Dyrness effective management, and recognition of the 1988). Euro-Americans practiced fire suppres- value of oak woodlands will therefore be impor- sion in the Willamette Valley, which has sub- tant to maintaining this region’s wildlife diversity. sequently promoted development of closed- canopy woodlands composed of Oregon Oregon white oak, the most common oak white oak (Quercus garryana), Douglas-fir species in the Willamette Valley and surround- (Pseudotsuga menziesii), big-leaf maple (Acer ing foothills, is most competitive at xeric or macrophyllum), and other tree species “poor” sites, which are areas that are dry and (Thilenius 1968). Agricultural land practices, well-drained and areas that are droughty during

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

 the summer and poorly drained during the wet ❖ Review literature from studies relating season (Stein 1990). In the absence of fire, to oak woodland management and res- Oregon white oaks are normally outcom- toration studies relevant to conditions peted at mesic sites not subjected to intense observed at the study sites. drought in summer (Thilenius 1964, 1968; Stein 1990). Therefore, Oregon white oak is This assessment was in support of the often confined to borders or edges between district’s efforts to preserve and effectively two communities (McCulloch 1940), such as manage oak woodland habitats for associated dry meadows and mature forests. wildlife species (USDI 1995).

Assessment Project Area Objectives The oak woodlands surveyed lie within the McKenzie and South Valley Resource Areas In 1998, existing oak woodlands in the (RA’s) administered by BLM’s Eugene District Bureau of Land Management’s (BLM’s) in Lane County, Oregon (Figure 1). Sites Eugene District in Oregon were identified within the McKenzie RA occur on the approx- and an assessment was conducted at selected imate boundary of the Willamette Valley and sites. The objectives of the assessment were Western Cascade physiographic provinces to: (Franklin and Dyrness 1988); those in the South Valley RA occur on the approximate ❖ Describe the general physical and veg- boundary of the Willamette Valley and Coast etation characteristics and conditions of Range provinces. These foothills are character- each oak woodland and delineate wood- ized by gentle slopes and valleys. Elevation of land boundaries on aerial photos. these sites was <2000 feet. ❖ Compare the current condition of select- The climate of the Willamette Valley and sur- ed sites with historical records using rounding foothills is temperate, with cool, wet Oregon Natural Heritage Program veg- winters and hot, dry summers. In Eugene, etation classifications interpreted from mean temperatures are 41 ºF in January General Land Office surveys conducted (min. 35 ºF) and 67 ºF in July (max. 81 ºF); during the 1850’s. the average annual temperature is 53 ºF. Annual precipitation averages 49.5 inches in ❖ Identify wildlife species most likely asso- Eugene, with more than 70 percent of rainfall ciated with the oak woodlands in the occurring from November through March region surveyed based on distributions (Oregon Climate Service 1998). and habitat requirements of oak associ- ated species and assess general suitability The project area consists of a mosaic of veg- of available oak habitat for potentially etation characteristic of the pine-oak-fir occurring species. (Pinus-Quercus-Pseudotsuga) vegetation zone

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

 (Franklin and Dyrness 1988). This mosaic is madrone (Arbutus menziesii), with poison composed of coniferous forests, oak woodlands, oak (Rhus diversiloba), oceanspray, and hazel as meadows, and forested wetland and riparian the most common shrubs. Wetland and ripar- areas. Coniferous forests are dominated mainly ian areas are commonly dominated by big-leaf by Douglas-fir with grand fir (Abies grandis), maple in addition to Oregon ash (Fraxinus incense-cedar (Calocedrus decurrens), ponder- latifolia), which often extends into less moist osa pine (Pinus ponderosa), western redcedar areas. California black oak (Q. kelloggi) is limited (Thuja plicata) and western hemlock as asso- to the southern parts of the surveyed area ciates. Big-leaf maple and Oregon white oak (Franklin and Dyrness 1988; and personal are common hardwood associates. Dominant observations). understory species include dwarf Oregon grape (Berbis nervosa), California hazel (Corylus Private and public lands are highly interspersed cornuta var. californica), salal (Gaultheria shal- on the McKenzie and South Valley RA’s. lon), oceanspray (Holodiscus discolor), and Forestry and grazing have dominated land use sword fern (Polystichum munitum). Scattered on both public and private lands in the foothills. grassy meadows on drier, south-facing slopes The floodplain of the Willamette River is the often contain Oregon white oak and pacific most densely populated region in Oregon.

Figure 1. Map of Lane County, Oregon, showing the distribution and location of the 13 survey sites.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT



METHODSMETHODS

(height = 60-80 feet) that were usually in Site Selection dominant canopy positions or codominant Clusters of oak trees in the McKenzie and with Douglas-fir or Oregon ash. Woodland South Valley RA’s were initially identified sites typically bordered or were embedded from field records and intra-agency commu- within Douglas-fir-dominated conifer nications. These locations were verified using forests or wetland areas consisting of aerial photos and field reconnaissance. The Oregon ash and big-leaf maple. sites to be surveyed were then prioritized based on size and potential for timber and habitat management. One of the selected sites Oak Patch Delineation was actively managed for oak restoration prior Between August 12 and September 24, 1998, to this survey. Selected sites were located 13 sites were visited to delineate oak patches. within BLM parcels of forested land ranging At most sites, oak trees were distributed along from approximately 10-100 acres in size. a gradient of species composition: high con- centrations of oaks arranged in small clusters Site Classification or forming a ring around a meadow and gradu- ally becoming less common in a forest matrix, The sites were classified into two general types usually dominated by Douglas-fir. Patch of oak communities: boundaries were based on five factors that ❖ Meadow-type: Most oaks distributed along were evaluated by the surveyor at each site: the perimeter of a small meadow having shallow soils, often on south-southwest 1. Minimum patch area >1 acre. aspects. Relatively larger oaks (height = 2. Canopy composition: tree canopies at each 30-60 feet) occurred along the meadow patch were usually composed of more perimeter with smaller individuals (often than 50 percent oak crowns. with shrubby form, 15-20 feet in height) scattered in central regions of meadows and 3. Land ownership: non-BLM lands were were usually the only tree species growing excluded. in this central area. Meadows and associated oaks were generally elliptical in shape, sur- 4. Topography: some boundaries were defined rounded by a Douglas-fir-dominated conifer by sharp changes in slope or ridge lines. matrix. 5. “Compactness”: boundaries were adjusted ❖ Woodland-type: Woodlands were char- to facilitate management within oak acterized by a uniform cohort of oaks patches and surrounding forest.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

 Site Descriptions

The topographic features, vegetation in 25 oak patches, which are listed in structure,and composition were characterized Table 1.

Table 1. List of surveyed sites, patch acronyms, and associated community types.

Community Site Patch Acronym Type

Anthony Creek ANTH-1 Meadow ANTH-2 ANTH-3 Bates BATES Meadow Cougar Mountain COUG-1 Woodland COUG-2 Eagle’s Rest EAGL-1 Woodland EAGL-2 Fox Hollow FOX Woodland Gilkey Creek GILK-1 Meadow GILK-2 GILK-3 Kloster Mountain KLOS-1 Meadow KLOS-2 KLOS-3 KLOS-4 Rattlesnake RATT-1 Meadow RATT-2 RATT-3 Sears Road SEARS Woodland Seventy-Ninth SEVENT Meadow Weiss Road WEISS Meadow Wendling WEND-1 Meadow WEND-2 Wills Road WILLS Woodland

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

 Topography Patch-level metrics (e.g., patch area, aspect, with at least a one-third difference in height slope, elevation) and the location of patch between successive layers. For each layer, the centers including the respective units, methods, absolute percent canopy cover for the patch, and instruments used, are shown in Table 2. average top height of the layer, and total number of trees per acre were determined Patch Composition (Table 3). For the bottom canopy layer, trees <10 feet in height were not counted. To characterize the composition of each layer, Canopy the percent cover of the five most dominant A modified form of guidelines from Cadwell species cohorts (species in an individual size (1998) was used to classify the vertical stra- class) with a relative canopy layer cover ta of tree canopies. Tree cover for each patch >5 percent was recorded (Table 4). was divided into a maximum of three layers Additional species observed were noted.

Table 2. Physical descriptors of individual patches including units and methods/instruments used.

Variable Unit Method/Instrument

Area Nearest whole acre Rangefinder and hip-chain Aspect (average) Degrees Compass Slope (average) Degrees Clinometer Elevation Nearest 50-foot interval Topographic map Location UTM-Lat/Long GPS

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

 Table 3. Variables and methods used to characterize canopy layers within patches (three layers maximum).

Variable Unit Method/Instrument

Canopy cover Percent of patch cover Ocular estimate, absolute for each layer Height Nearest 10 feet Average top of layer, rangefinder and clinometer Trees per acre Nearest whole number 100 percent tree count

Table 4. Descriptive variables for tree composition of individual canopy layers.

Variable Unit Method/Instrument

Percent of layer Percent (multiple of 5) Relative abundance of top five species by diameter class (min. 5 percent) Diameter at breast height Diameter classes (inches): Ocular estimate; dbh tape, (dbh) 0-5, 5-10, 10-15, 15-20, tape stick 20-30, 30-50

Snags

The following data were recorded for each present and little sign of decay; b. snag (completely dead tree) >10 inches dbh Soft – trees commonly with tops within each patch: broken off, lacking branches and bark (except Pseudotsuga menziesii 1. Type: either oak or other species. and Abies grandis), with extensively decayed sapwood and heartwood 2. Diameter class: 10-20 inches or >20 (Parks et al. 1997). inches.

3. Structural classifications: a. Hard – trees with most of their branches and bark

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

 Shrubs and Nonnative Plants to study oak diameter growth rates in the absence of competition. When open-form The five most common woody shrubs were trees were not present, cores were taken recorded, along with percent of patch cover from relatively older trees with the wid- (nearest 5 percent). The presence of certain est crowns, and consequently, the least nonnative plants common to these habitats (relative) amount of competition from was also noted. neighbors. Core samples were taken at breast height and were used to estimate Oak Growth and Regeneration growth rates or rings per inch (RPI) and age (either by counting growth rings or To understand factors affecting oak growth in using RPI x tree radius at breast height if each site, an additional set of descriptors and cores were not complete). Height, diam- variables was collected: eter at breast height, and mean crown radius were also measured for each cored 1. The general relative soil characteristics— tree. In addition, at two of the meadow- moisture level, depth, and the presence type communities, a single tree was of rocky outcrops—were noted. harvested along with numerous shorter, shrubby clusters of oak stems. The com- 2. To assess environmental and competi- plete cross section produced from these tive factors potentially affecting oak stems provided a more accurate estimate growth, as well as the quality and of age and growth rates in these thin, quantity of wildlife habitat, the general slow-growing stems. form of oaks according to the degree of openness/width of tree crowns and loca- tions within the patch where form varied Additional Descriptive were noted. Information 3. The relative abundance of oak regenera- One or two photographs were taken (using a tion (oak trees with dbh <3 inches and 35mm SLR camera with a 28mm lens) and height <10 feet) in each patch was noted maps were sketched of each patch to provide using ocular estimation: additional visual references of oak distribution. Evidence of grazing (e.g., presence of fencing) a. Absent. and tree harvesting, as well as off-road use, b. Rare, ~1-20 stems per acre. vandalism, and dumping, was recorded at each c. Common, ~21-50 stems per acre. location. In some sites, searches were performed d. Abundant, >50 stems per acre. outside of the patch boundaries to determine the presence, distribution, and general condition 4. In addition, increment core samples of neighboring oak communities and to assist in were obtained from one or two trees at the understanding of the vegetation history at each patch. Open-form trees were cored that site.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

 <66 feet, typically <33 feet. Stands may Oak Distribution include fire-sensitive species such as cedar, Patterns hemlock, and maple.

A combination of survey information and the ❖ Woodland: Distance to witness trees most- interpretation of historic land survey records ly 66-132 feet. Stands usually lack cedar, was used to characterize the vegetation history hemlock, and maple. and trends occurring at each site. During the 1850’s, the U.S. General Land Office (GLO) ❖ Savanna: Openings with grass, fern, hazel, conducted land surveys in the Willamette and shrub oak understory. Distance to wit- Valley to designate township and sections ness trees mostly >132 feet. and determine lands suitable for settlement. Experienced surveyors used large “bearing” or ❖ Prairie: Distance to witness trees mostly “witness” trees to mark township and sectional 132-528 feet. Understory with grass or boundaries in addition to making general vege- fern, with no reference to dense shrub tation and environmental descriptions (Habeck growth. 1961). Christy et al. (1996) have used the transcriptions and plat maps of the GLO sur- veyors and soil maps to create classifications of historic vegetation types for the surveyed areas Wildlife Habitat within Lane County. These classifications have Associations been transcribed into databases, which can be used to produce geographic information sys- tem (GIS) maps of historical vegetation (see Wildlife Species Christy et al. 1996 for detailed protocol). To identify species most likely occurring in the surveyed sites in Lane County, Oregon, Two vegetation classifications were available a list of wildlife species associated with the from these maps for characterizing historic observed habitats was compiled using infor- vegetation at the oak sites: major vegetation mation from Brown (1985) and Csuti et types and subcategories of these major types. al. (1997). Three plant communities were Subcategory information was not available for selected from Brown (1985) that most closely all sites and GLO survey information was represented those at the surveyed sites: dry- completely lacking for two sites. The four hillside/grass-forb, deciduous-hardwood; and major types of vegetation occurring at or conifer-hardwood. In order to focus on species near sites are listed below with definitions most strongly associated with the selected com- according to Christy et al. (1997): munity types, only species breeding in these habitats were listed. The use of edge habitats ❖ Closed forest upland: Distance to witness and specific information on required habitat trees (large, marker trees used to establish structural components (snags and cavities) for boundaries of townships and sections) was the selected species were also noted. Because

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

10 Brown (1985) does not directly specify spe- using relationships described by Goodrum et cies associated with oaks, habitat information al. (1971). Using counts of trees per acre and from Csuti et al. (1997) was included to help the relative abundance of oak cohorts (dbh class) identify which of the selected species are in each canopy layer, as well as additional field known to use oak woodlands. Some of the notes, the number of trees was estimated by size limited oak-habitat relationship information class at each surveyed patch. The mast produc- for the Willamette Valley was included by tion was then calculated for the size classes pro- listing relative bird abundance information ducing acorns according to the following approx- from Hagar and Stern (1997). From this list imated yields from Goodrum et al. (1971; and other sources, ten species that are com- table 2): 10-15 inches dbh = 5.48 pounds; monly associated with oaks were chosen and 15-20 inches = 11.05 pounds; 20-25 inches the use of oak habitat for five of these species = 16.65 pounds; 25-30 inches = 20.5 pounds. was described.

Formal wildlife surveys were not conducted; Restoration however, any sign or direct observation of wildlife species was noted during vegetation and Management surveys. Literature Review Habitat Components Oak woodland management and restoration literature that addressed the specific condi- Oak-related literature was reviewed to evaluate tions observed at the surveyed sites was the relationships between animal populations reviewed in order to aid future management and Oregon white oak plant communities. decisions for these areas. Acorn production in each patch was estimated

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

11

RESULTSRESULTS AND AND DISCUSSIONDISCUSSION

Overview of BLM Sites

Physiography

The BLM sites surveyed ranged from 750 Oregon ash, grand fir, and big-leaf maple were to 2,000 feet above sea level (Table 5). The also common. sites most often occurred on xeric, south and southwest hill slopes, although some sites (e.g., Oregon white oak occurred in small patches Eagle’s Rest, Fox Hollow) occurred in lower top- (maximum area = 5 acres) at the 13 BLM ographic positions and had moist or wet soils. sites, and oak crowns usually formed a minor component of the overall canopy (mean = Plant Community 18 percent cover, max. = 54 percent cover) (Table 7). Oak trees >15 inches dbh were Composition and Structure rare at the BLM sites and dry sites on south and southwest aspects were dominated by a Dominant tree canopy positions in woodland- cohort of shrubby oaks <5 inches dbh. type patches and adjacent to meadow-type patches were most often occupied by Douglas- Snags were uncommon structural features fir, with incense-cedar and Oregon white oak in the surveyed BLM woodlands (Table 8). occasionally codominant (Table 6). Pacific The greatest total density measured was 8.5 madrone was often observed on xeric sites. snags/acre (COUG-1) and snags >20 inches

Table 5. Summary of physical characteristics of surveyed patches (N= 25 for all variables).

Elevation (feet) Slope (°) Aspect (°) Acres

Mean 1,264.0 18.9 187.6 2.6 Max. 2,000.0 47.0 290.0 5.0 Min. 750.0 5.0 72.0 1.0

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

13 dbh were very rare (maximum observed den- (Table 9). Oceanspray and Himalayan black- sity = 0.75/acre). Although the number or berry (Rubus discolor) were also observed at volume of dead branches in the surveyed sites more than half the patches surveyed. was not measured, it was subjectively estimat- ed that dead branches on live oak trees rep- Most sites were occupied by one or more resented a considerable fraction of the small plant species listed by the BLM as nonnative diameter (<10-inch diameter) cavity nesting plants (Table 10); however, only Himalayan substrate in these woodlands. blackberry and Scotch broom were abundant within oak patches. Poison oak was the most frequently observed shrub (88 percent of patches) at oak patches

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

14 Table 6. Summary of the most abundant tree cohorts (based on species and size) occurring in canopy layers in each surveyed patch. Patches are listed according to community type: M= meadow, W= woodland. Cohort 1 and 2 (C1 and C2) represent the species of the two most dominant tree cohorts for each layer; a dashed line indicates that either only one species occurred in the top layer or the canopy consisted of only two layers (top and bottom). Multiple cohorts indicate equal dominance. ABGR= grand fir; ACMA= big leaf maple; ARME = Pacific madrone; CADE= incense-cedar; FRLA = Oregon ash; PSME = Douglas-fir; QUGA = Oregon white oak.

Canopy Layer

Community Top Middle Bottom Patch Type C1 C2 C1 C2 C1 C2

ANTH-1 M PSME CADE QUGA ARME QUGA QUGA ANTH-2 M ARME ARME - - QUGA ARME ANTH-3 M PSME - ARME ARME QUGA ARME/PSME BATES M PSME PSME QUGA ARME QUGA QUGA GILK-1 M PSME PSME QUGA QUGA QUGA CADE GILK-2 M PSME CADE CADE PSME QUGA PSME GILK-3 M PSME PSME QUGA CADE/PSME QUGA PSME KLOS-1 M PSME - - - QUGA ARME/PSME KLOS-2 M PSME CADE QUGA ACMA/ARME/CADE QUGA QUGA KLOS-3 M PSME - QUGA ACMA/ARME/CADE QUGA QUGA/PSME KLOS-4 M PSME - QUGA ARME/QUGA QUGA ARME/PSME RATT-1 M PSME PSME QUGA PSME QUGA PSME RATT-2 M PSME PSME QUGA ACMA/PSME QUGA ACMA/PSME RATT-3 M PSME PSME QUGA QUGA QUGA ACMA/PSME SEVENT M PSME - QUGA ARME/QUGA/PSME QUGA QUGA WEISS M PSME PSME PSME PSME PSME QUGA WEND-1 M QUGA QUGA - - QUGA QUGA WEND-2 M PSME - QUGA QUGA QUGA QUGA COUG-1 W PSME ABGR/PSME QUGA ABGR ABGR QUGA COUG-2 W CADE QUGA - - ABGR CADE EAGL-1 W QUGA QUGA - - FRLA ABGR/PSME/QUGA EAGL-2 W QUGA PSME PSME FRLA FRLA PSME FOX W PSME PSME PSME ACMA/FRLA/PSME PSME QUGA SEARS W PSME PSME QUGA QUGA PSME QUGA WILLS W PSME PSME QUGA QUGA QUGA QUGA

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

15 Table 7. Summary of selected oak size characteristics for each surveyed patch. Patches are listed according to community types: M= meadow, W= woodland. For each patch, the size class, percent cover for the entire patch, and the respective canopy layer height values are given for the oak cohort with the greatest patch cover and the largest size class (dbh).

Community Area Oak Cohort with Greatest Patch Cover Oak Cohort with Largest Diameter Class

Patch Type (acres) dbh Class Percent Layer Height dbh Class Percent Layer Height (in) Cover (feet) (in) Cover (feet)

ANTH-1 M 1 0-5 14 20 10-15 1 40 ANTH-2 M 2 5-10 3 30 10-15 1 30 ANTH-3 M 2 5-10 4 30 5-10 4 30 BATES M 3 0-5 15 25 5-10 12 40 GILK-1 M 2 10-15 12 50 10-15 12 50 GILK-2 M 1 5-10 3 30 15-20 2 70 GILK-3 M 2 10-15 8 60 10-15 8 60 KLOS-1 M 3 5-10 8 50 5-10 8 50 KLOS-2 M 3 0-5 18 20 5-10 2 40 KLOS-3 M 5 0-5 8 20 5-10 4 40 KLOS-4 M 3 0-5 21 20 10-15 1 40 RATT-1 M 4 5-10 8 40 10-15 2 40 RATT-2 M 3 10-15 8 30 10-15 4 50 RATT-3 M 4 5-10 8 20 10-15 4 40 SEVENT M 2 0-5 54 15 5-10 14 40 WEISS M 3 15-20 2 70 15-20 2 70 WEND-1 M 2 5-10 21 35 10-15 3 35 WEND-2 M 3 5-10 14 30 5-10 14 30 COUG-1 W 2 10-15 21 70 15-20 7 70 COUG-2 W 2 10-15 21 80 10-15 21 80 EAGL-1 W 1 10-15 45 80 10-15 45 80 EAGL-2 W 2 10-15 48 80 15-20 8 80 FOX W 2 5-10 18 40 10-15 7 70 SEARS W 5 10-15 28 80 15-20 3 80 WILLS W 2 10-15 28 80 15-20 14 80

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

16 Table 8. List of snag counts and characteristics for each surveyed patch. Patches are listed according to community type: M = meadow and W = woodland. Size classes are dbh (inches). Refer to Methods section for definition of hard and soft characteristics.

Oaks Other Species

Community Hard Soft Hard Soft Patch Type 10-20 >20 10-20 >20 10-20 >20 10-20 >20 Total

ANTH-1 M 0 0 0 0 0 0 0 0 0 ANTH-2 M 0 0 0 0 0 0 0 0 0 ANTH-3 M 0 0 0 0 0 0 0 0 0 BATES M 0 0 0 0 0 0 3 4 7 COUG-1 W 0 0 0 0 3 1 11 2 17 COUG-2 W 1 0 1 0 7 0 1 0 10 EAGL-1 W 0 0 4 0 0 0 2 0 6 EAGL-2 W 2 0 3 0 0 0 0 0 5 FOX W 0 0 1 0 1 2 1 3 8 GILK-1 M 0 0 0 0 0 1 0 0 1 GILK-2 M 0 0 0 0 0 0 0 0 0 GILK-3 M 0 0 0 0 2 5 0 0 7 KLOS-1 M 0 0 0 0 0 0 0 0 0 KLOS-2 M 0 0 0 0 0 0 0 0 0 KLOS-3 M 0 0 0 0 0 0 0 0 0 KLOS-4 M 0 0 0 0 0 0 0 0 0 RATT-1 M 0 1 0 0 0 0 0 4 5 RATT-2 M 1 0 0 0 0 0 0 0 1 RATT-3 M 0 0 0 0 2 0 2 0 4 SEARS W 2 1 8 2 0 1 3 0 17 SEVENT M 0 0 0 0 1 0 0 0 1 WEISS M 0 0 1 0 2 2 1 0 6 WEND-1 M 0 0 0 0 0 0 0 0 0 WEND-2 M 0 0 0 0 0 1 0 0 1 WILLS W 1 0 4 0 1 1 2 0 9

Total 7.0 2.0 22.0 2.0 19.0 14.0 26.0 13.0 105.0 Mean 0.3 0.1 0.9 0.1 0.8 0.6 1.0 0.5 4.2

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

17 Table 9. Percent occurrence of the most dominant shrubs in the surveyed patches. Numbers in parentheses = number of patches. Total number of patches surveyed = 25.

Shrub Percent Occurrence

Poison oak 88 (22) Oceanspray 60 (15) Himalayan blackberry 56 (14) California hazel 44 (11) Orange honeysuckle 40 (10) Tall Oregon grape 36 (9) Trailing blackberry 36 (9) Common snowberry 32 (8)

Table 10. Percent occurrence of nonnative plants observed in the surveyed patches. Numbers in parentheses = number of patches. Total number of patches surveyed = 25.

Nonnative Plant Percent Occurrence

St. John's wort 64 (16) Tansy ragwort 60 (15) Himalayan blackberry 56 (14) Bull thistle 40 (10) Scotch broom 32 (8) Evergreen blackberry 32 (8) Canada thistle 8 (2)

Oak Growth and Regeneration growth (RPI) =12.5 among “forest-form” or closed canopy trees (12-21 inches dbh). Diameter (dbh), height, diameter growth Stein (1990) reported that 16-20 RPI is typ- (RPI), and estimated ages were measured for ical among Oregon white oaks. Relationships 20 sample Oregon white oaks located on the between sample tree attributes are repre- BLM sites (Table 11). On average, diameter sented in Figures 2A-D. Estimates of oak growth was 21.0 RPI (range = 7.8-45.8). regeneration for each patch are shown in Thilenius (1964) reported mean diameter Table 12.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

18 Table 11. Growth and age information for sampled oak trees. Patches are listed according to community type: M = meadow and W = woodland. dbh= diameter at breast height, RPI = rings per inch. The #1 and #2 following a patch name indicates two different cores taken at the same patch.

Community dbh Height Estimated Mean Crown Patch Type (inches) (feet) RPI Age (years) Radius (feet)

ANTH-3 M 8.5 32 22.2 59 9.5

BATES M 11.0 30 21.3 88 8.3 GILK-2 M 17.0 64 13.0 111** 17.3 GILK-3 M 13.0 75 27.4 178** 10.0 KLOS-1 M 11.5 50 12.3 58 9.5 KLOS-3* M 3.5 21 45.8 50 KLOS-4 M 7.0 30 19.0 53 7.5 RATT-3 M 16.0 35 8.3 67** 14.0 SEVENT M 14.0 42 26.7 187** 8.8 WEISS (#1) M 11.5 28 7.8 39 12.5 WEISS (#2) M 15.0 70 18.0 100 10.8 WEND-2 (#1) M 7.5 30 22.1 50 5.0 WEND-2* (#2) M 3.0 24 33.6 47 COUG-1 W 19.5 62 25.7 251** 10.8 COUG-2 W 22.0 70 15.0 165** 9.3 EAGL-1 W 12.5 85 22.5 134 13.0 EAGL-2 W 15.5 80 16.7 130** 13.3 FOX W 12.0 65 28.4 170** 8.8 SEARS W 21.0 62 15.8 166** 12.8 WILLS W 14.5 85 17.8 129** 9.

Mean 12.8 52.0 21.0 68 10.6

* cuttings or very small stems for which canopy radii were not measured. ** age was estimated (rings per inch x radius at breast height).

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

19 A B

90 300 80 s) 250 70 60 200 50 150 40 30 100 ree height (feet) T 20 50 10 Estimated Age (year 0 0 0 5 10 15 20 25 0 20 40 60 80 100

dbh (inches Height (feet)

C D

300 30

s) 250 25

200 h 20

150 15

100 10 Rings per inc 50 5 Estimated Age (year

0 0 0 5 10 15 20 25 0 5 10 15 20

dbh (inches) Mean crown radius (feet)

Figures 2A-D. Relationships between (A) tree height and dbh, (B) tree age and height, (C) tree age and dbh, and (D) growth rate (rings per inch) and mean crown radius for sampled oaks.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

20 Table 12. Estimates of oak regeneration abundance (oak stems with dbh <3 inches and height <10 feet) in the surveyed patches. Patches are listed according to com- munity type: M = meadow, W = woodland. Rare ~1-20 stems per acre; common ~21-50 stems per acre. Area estimated to nearest acre.

Oak Community Area Patch Regeneration Type (acres)

ANTH-1 Rare M 1 ANTH-2 Absent M 2 ANTH-3 Absent M 2 BATES Common M 3 GILK-1 Common M 2 GILK-2 Common M 1 GILK-3 Common M 2 KLOS-1 Rare M 3 KLOS-2 Common M 3 KLOS-3 Common M 5 KLOS-4 Common M 3 RATT-1 Rare M 4 RATT-2 Rare M 3 RATT-3 Rare M 4 SEVENT Rare M 2 WEISS Rare M 3 WEND-1 Rare M 2 WEND-2 Common M 3 COUG-1 Rare W 2 COUG-2 Rare W 2 EAGL-1 Rare W 1 EAGL-2 Rare W 2 FOX Common W 2 SEARS Rare W 5 WILLS Common W 2

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

21 Oak growth rate: sample tree height was 30 Site Descriptions feet (dbh = 11.0 inches) at 88 years.

Anthony Creek Regeneration: abundant vegetative sprouts from live trees. Site: south aspect; soil appears shallow in meadow; xeric. Management issues: sensitive plant area.

Oak distribution: three clusters of small 1850’s land cover: woodland. (<2-acre) meadow-type communities.

Vegetation structure: top canopy layers dominat- Cougar Mountain ed by Douglas-fir, Pacific madrone, and incense- Site: south aspect; hillside position; moist soil cedar; oak canopy cover ~14 percent; oaks >5 (spring observed near Coug-2). inches dbh are rare (<5 percent cover). Oak distribution: two small (2-acre) wood- Oak growth rate: sample tree height was 32 land-type communities; oaks also occurred on feet (dbh = 8.5 inches) at 59 years. adjacent private lands to the east at Coug-1.

Regeneration: oak seedlings were very rare; some Vegetation structure: top canopy layer domi- sprouts on fire-scarred trees were observed; nated by Douglas-fir, incense-cedar, grand fir, conifer regeneration is rare. and oak; oak canopy cover ~21 percent; largest oaks are in 25- to 30-inch dbh class; conifer Management issues: none noted. succession apparent; Himalayan blackberry cover >20 percent. 1850’s land cover: closed upland forest. Oak growth rate: sample tree #1 height was Bates 62 feet (dbh = 19.5 inches) at ~250 years; sample tree #2 height was 70 feet (dbh = 22.0 Site: hilltop position; steeper slopes than inches) at ~165 years. average; xeric to mesic conditions. Regeneration: very rare oak reproduction Oak distribution: single meadow-type com- observed; conifer regeneration is common. munity; approximately 3 acres; oaks inter- spersed with madrone and Douglas-fir. Management issues: compacted soils from bike trail (Coug-1); old fencing (Coug-2). Vegetation structure: top canopy layer domi- nated by Douglas-fir; oak canopy cover ~15 per- 1850’s land cover: prairie; closed upland forest. cent; largest oaks are in 10- to 15-inch dbh class; dense shrub layer; poison oak cover >90 percent.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

22 Eagle’s Rest is located approximately 200 feet south of the patch across a small stream. Site: northwest aspect; lower slope position; seasonal wetlands observed. Vegetation structure: top canopy layer dominat- ed by Douglas-fir; oak canopy cover ~18 per- Oak distribution: two small (<2-acre) wood- cent; largest oaks are in 15- to 20-inch dbh class; land-type communities; oaks continue to adja- this was the only BLM site where California cent private lands. black oak was observed (Quercus kelloggi), rep- resenting approximately 20 percent of all oaks Vegetation structure: top canopy layer is at this site; oaks in middle and bottom canopy dominated by oak and Douglas-fir; oak canopy position appeared to be of low vigor; conifer cover ~50 percent; largest oaks are in 20- to succession apparent; dense shrub layer. 25-inch dbh class; numerous dead branches on live trees; Himalayan blackberry cover Oak growth rate: sample tree height was 65 >90 percent at Eagl-2. feet (dbh = 12.0 inches) at ~170 years.

Oak growth rate: sample tree #1 height was 85 Regeneration: oak seedlings common in canopy feet (dbh = 12.5 inches) at 134 years; sample gaps; conifer regeneration is also common. tree #2 height was 80 feet (dbh = 15.5 inches) at ~130 years. Management issues: insect infestation problem on oak foliage. Regeneration: oak reproduction is rare; Oregon ash and Douglas-fir regeneration is common. 1850’s land cover: woodlands and forests composed of Douglas-fir, chinquapin, and Management issues: fencing on west property madrone on south slopes; Douglas-fir and big- line at Eagl-2; blackberry density indicates leaf maple on north slopes; also incense-cedar, possible grazing; minor amounts of garbage. oak, grand fir, western redcedar, Pacific yew, red alder, and pacific dogwood. 1850’s land cover: described as “mountainous and unfit for habitation.” Gilkey Creek Fox Hollow Site: south-facing slopes; dry soils in meadows.

Site: lower slope-riparian position; moist soil. Oak distribution: three small (<2-acre) mead- ow-type communities; oaks continue to bor- Oak distribution: single, small (~2-acre) wood- dering private lands at each patch. land-type community; a reconnaissance of neighboring areas revealed scattered oaks (height Vegetation structure: top-canopy dominated range 30-70 feet, 5-15 inches dbh), one mas- by Douglas-fir, oak canopy cover ~12 percent; sive individual (approximately 26 inches dbh) largest oaks in15- to 20-inch dbh class; majority

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

23 of oaks 10 to15 inches dbh; relatively tall (30- Regeneration: common, mainly vegetative to 60-foot) oaks in meadow center at Gilk-1; all sprouting. trees overtopped in Gilk-2. 1850’s land cover: unclassified. Oak growth rate: sample tree #1 height was 64 feet (dbh = 17.0 inches) at ~111 years; sample tree #2 height was 75 feet (dbh = 13 inches) Rattlesnake at ~178 years. Site: upslope meadows varying in aspect.

Regeneration: common, mainly vegetative Oak distribution: three meadow-type commu- sprouting; conifer regeneration is common. nities (<4 acres); reconnaissance south of Ratt- 2 revealed three small oak clusters in openings Management issues: compacted off-road trails of ~0.75 acres (height range 30-50 feet, with (Gilk-1 and -2). one individual >80 feet, ~25 inches dbh; two clusters were likely on private land). 1850’s land cover: savanna and prairie border- ing closed forest upland. Vegetation structure: upper canopy dominat- ed by Douglas-fir; oak canopy cover ~8 per- cent; largest oaks 25-30 inches dbh, but rare Kloster Mountain (<1 percent cover); majority of oaks growing under conifers. Site: steep hillside meadows, with south aspect dry soils and numerous rocky outcrops. Oak growth rate: sample tree height was 35 feet (dbh = 16.0 inches) at ~67 years. Oak distribution: four meadow-type communi- ties (<5 acres); embedded in a conifer matrix. Management issues: sensitive plant site (Ratt-1).

Vegetation structure: upper canopy dominated Regeneration: oak and conifer regeneration by Douglas-fir and some incense cedar; oak are rare. canopy cover ~21 percent; largest oaks 10-15 inches dbh; oaks >10 inches dbh rare (<10 1850’s land cover: woodland and closed for- percent cover). est upland.

Oak growth rate: sample tree #1 height was 50 feet (dbh = 11.5 inches) at 58 years; sam- Sears Road ple #2 height was 21 feet (dbh = 3.5 inches) Site: lower slope bordering forested uplands, at 50 years; sample tree #3 height was 30 feet riparian area, and open savanna. (dbh 7.0 inches) at 53 years. Oak distribution: single woodland-type Management issues: minor amount of logging community (~5 acres) merging with open operation debris. grassland/savanna.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

24 Vegetation structure: upper canopy dominated Regeneration: oak regeneration is rare; conifer by Douglas-fir; oak canopy cover ~28 percent; regeneration is common. large open grown oaks (30-40 inches dbh; <1 percent cover) overtopped by conifers 1850’s land cover: closed forest upland. at woodland/savanna edge; Himalayan black- berry cover (>90 percent cover) mainly under closed canopy woodland. Weiss Road

Oak growth rate: sample tree height was 62 feet Site: lower slope meadow; bordering riparian (dbh = 21.0 inches) at ~166 years. area.

Management issues: fenceline on north-south Oak distribution: single meadow-type com- property boundary. munity (~3 acres total); adjoining private land to north, which contains oaks with large relic Regeneration: oak regeneration is rare; conifer oak snag. regeneration is common. Vegetation structure: upper canopy dominated 1850’s land cover: prairie. by Douglas-fir; oak canopy cover ~2 percent, largest oaks are in 20- to 25-inch dbh class.

Seventy-Ninth Oak growth rate: sample tree #1 height was 28 feet (dbh = 11.5 inches) at 39 years; sample Site: hillside meadow with northwest aspect; tree #2 height was 70 feet (dbh = 15.0 inches) well-drained soils; embedded in forested uplands. at 100 years. Oak distribution: single long thin meadow-type Management issues: site adjacent to logging community (could be classified as unique wood- road; dumping along road near patch. land-type with shrub-form oaks) (~2 acres); ~25 oaks (50-70 feet) observed in canopy gap 100 Regeneration: oak regeneration is rare; conifer yards northeast of surveyed patch. regeneration is common. Vegetation structure: upper canopy dominated 1850’s land cover: woodland. by Douglas-fir; oak canopy cover ~54 percent; majority of trees with thin shrubby stems; largest oaks are 10-15 inches dbh; dense shrub Wendling layer (oceanspray cover ~70 percent). Site: lower slope position; dry soils. Oak growth rate: sample tree height was 42 feet (dbh =14.0 inches) at ~187 years. Oak distribution: two meadow-type commu- nities (<3 acres). Management issues: water line at extreme east end of patch (exact property line not defined).

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

25 Vegetation structure: upper canopy dominated Management issues: evidence of oak harvest- by Douglas-fir and oak; oak canopy cover ing near patch (1 stump 10-15 inches dbh). ~21 percent, largest oaks 15-20 inches dbh; management activities prior to surveys includ- Regeneration: oak regeneration is common; ed conifer snag creation and removal of dense conifer regeneration is common. scotch broom cover. 1850’s land cover: woodland and closed for- Oak growth rate: sample tree #1 height was est upland. 30 feet (dbh = 7.5 inches) at 50 years; sample tree #2 height was 24 feet (dbh = 3.0 inches) at 47 years. Oak Distribution

Management issues: patches adjacent to road. Patterns

Regeneration: oak regeneration is rare; conifer Regional Level regeneration is common. Most Oregon forests are dominated by 1850’s land cover: woodlands and forests conifers. Hardwoods often function as pio- composed of Douglas-fir, chinquapin, and neer species or are confined to local niches madrone on south slopes; Douglas-fir and big- (Franklin and Dyrness 1988). In western leaf maple on north slopes; also incense-cedar, Oregon, oak woodlands are concentrated in oak, grand fir, western redcedar, Pacific yew, the interior valleys (Franklin and Dyrness red alder, and pacific dogwood. 1988) where larger, fire-resistant oaks were able to survive the frequent fires that elimi- nated younger trees, creating open savanna and Wills Road prairies in many areas (Thilenius 1968). The increase in closed canopy conditions in oak Site: lower slope-riparian position; seasonally woodlands resulting from active fire suppres- wet soil. sion often favors seedling growth of conifers such as Douglas-fir (Barnhart et al. 1987). Oak distribution: small (<2-acre) single open Several authors (Sprague and Hansen 1946; woodland-type community; scattered oaks Habeck 1961; Thilenius 1964; Franklin and (height = 20–70 feet) bordering conifer matrix Dyrness 1988) have discussed potential climax in canopy openings. communities succeeding oaks under continued fire control. In general, they conclude that the Vegetation structure: upper canopy dominated climax community is most likely conifer for- by Douglas-fir; oak canopy cover ~28 percent; est dominated by grand fir and/or Douglas-fir; largest oaks 25-30 inches dbh. however, this will vary according to specific conditions and existing vegetation. Oak growth rate: sample tree #1 height was 85 feet (dbh = 14.5 inches) at ~129 years.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

26 Patch Level be “stable and self-perpetuating” (Thilenius 1968; Lorimer 1993 and references therein). In certain communities of the northern oak wood- Meadow-Type Sites lands in California, Oregon white oak is found The influence of environmental conditions and in “scrub” form with shallow soils and rocky competition are demonstrated by examining forested openings (Griffin 1977, Barnhart et al. the nature of oak and conifer growth and dis- 1987). Succession on these “poor” quality sites tribution typical of meadow-type sites. Figure in California, which are also often dominated by 3 depicts the typical tree distribution occurring grasses, is much slower compared to the typi- along hypothetical environmental gradients that cal oak woodlands of the Willamette Valley influence plant community composition and (Griffin 1977). Barnhart et al. (1987) note that physiognomy. Closer to the center of mead- a few foresters in northern California question ows, xeric, shallow soils and greater availability the ability of Douglas-fir to survive at marginal of light at ground level facilitate the persis- sites such as these meadows; during drought tence of oaks. Although oaks are capable of colo- years conifer species may lose access to water nizing these areas, their growth is extremely in the shallow soils and succumb to insect attack slow. Moving towards the edge of meadows, or branch cankers. A few large Douglas-firs slightly decreased sunlight intensity and denser were observed in the center of meadows; how- litter layers from surrounding vegetation cre- ever, a number of younger individuals in similar ate more mesic conditions and likely deeper locations showed evidence of needle loss. The soils. Taller oaks typically occurring in this current state of these sites suggests that succes- region of the meadow are probably respond- sion to conifer forest is possible but will occur at ing to the more favorable conditions, which a very slow rate, if at all. at some sites still may be too extreme for potentially competing conifer species. The Woodland-Type Sites edge of meadows seems to represent a cur- rent environmental threshold where nonoak Environmental conditions in woodland-type species, primarily Douglas-fir, are able to persist. sites, which were less extreme and less favor- Oaks also occur at this edge but, due to able for continued oak dominance, permitted decreased light availability and possibly con- much more potential for change in the canopy tinuing increases in conifer abundance, they composition. The age of the oaks in these often have smaller crowns and sparse leaf small woodlands suggests that they represent cover, with boles and limbs bending into the species that were capable of expanding into available light of the meadow. these seasonally wet and drier areas, which where formerly more open. However, as in the These small, xeric locations may represent closed-form oak stands of the Willamette a refuge for oaks within the conifer-domi- Valley, the environmental conditions created nated landscape. While oaks in more mesic by the increased oak densities have permitted sites were often overtopped, the poor qual- the initiation of succession to conifer forest. The ity of these sites may permit oak growth to canopy composition typical of woodland-type

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

27 sites (Figure 3) depicts an oak stand dominated of dense oak woodlands resulting from fire by closed-form oaks in midcanopy positions suppression. At forested oak stands in the with scattered conifers in the upper and lower Willamette Valley, Thilenius (1968) regu- canopy layers, which will likely slowly succeed larly found two-aged stands with a minimum the slower growing oaks. This form of succes- of one “relict” oak greater than 40 inches sion is also occurring in some very small areas dbh per acre. This represents the xmaximum outside of the xeric soils at meadow-type sites number of oaks per acre of this size observed where conditions permit conifer growth. during the surveys. The absence of relic trees, large snags, and stumps suggests that Although this type of succession is more typical conditions at these sites may not have been of woodland-type sites in the Willamette Valley, similar to the pre-European settlement oak the similarity may only reflect the relatively savanna Thilenius (1968) describes for the recent increases in oak density and formation Willamette Valley.

Meadow-Type Site

100 ft Decreasing light at ground Legend

Oaks

Meadow

Conifers Decreasing soil depth/water Patch Woodland-Type Site boundary

100 ft

Figure 3. Typical spatial pattern of oaks and conifers in meadow and woodland sites. Hypothetical environmental gradients influencing tree distribution in meadow sites are also shown.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

28 Effects of Fire Suppression settlement. Large and older open-form oaks, snags, and decaying logs were very rare or The primary causes attributed to the altera- absent. Although there were only a few signs tion of oak woodlands in the Willamette of oak harvesting, it is possible that the lack of Valley and surrounding areas include sup- snags and larger trees was due in part to past pression of fire, removal of oaks for fuel and removal. In some sites, fallen snags may have urban development, and grazing practices also been very decayed and were not detect- that alter soil conditions (Johannessen et al. ed during surveys. 1971; Towle 1982). Because the surveyed sites were generally isolated from urban dis- turbances and virtually no evidence of grazing Wildlife Habitat and cutting of oaks was found, changes in fire frequency have potentially had the greatest Associations effect on these oak woodlands. Species That Use Oak Woodlands The frequent and very extensive burning of the Willamette Valley prairies by Native Americans Most of the available data on wildlife use of oak documented by early explorers and settlers woodlands in the West comes from California. (Johannessen et al. 1971) must have reached According to Ryan and Carey (1995a), there are well into neighboring hills and valleys (Cole 331 terrestrial vertebrate species that use oak 1977). Natural fires may have also been fre- woodlands, including 120 mammals, 147 birds, quent in the Western Cascades, particularly in and 60 herpetofauna; Barrett (1980) suggested drier areas (Morrison and Swanson 1990). that at least 60 mammal species use oaks; Block and Morrison (1998) found 19 species Thilenius (1968) has described the effects of herpetofauna; and 110 bird species were of postsettlement fire regime on Willamette recorded using oak habitats by Verner (1980) Valley oak stands. He found that in the former in California. Gumtow-Farrior and Gumtow- oak savannas and prairies, younger forest-form Farrior (1992) listed 214 vertebrates that nest oaks had started growing near the time when and forge in Oregon oak woodlands. Hagar and both natural and human induced fires began to Stern (1997) observed 77 bird species using oak be suppressed, following the large immigration woodlands in the Willamette Valley, including of Euro-Americans in the 1840’s. A similar 43 residents, 29 migrants and 3 exotic species. trend of increased densities of oaks and other Pacific Wildlife Research (1998), using similar species <150 years old would be expected in study sites in Oregon, found 15 herpetofauna, oak woodlands in neighboring areas where including 2 salamanders, 1 newt, 4 frogs, 3 fires also regulated plant communities. lizards, and 3 snake species. Studies on oak woodlands in Oregon are limited because of The mean age estimated for forest-form, cored their limited distribution in a state dominated trees on BLM woodland-type sites (164 years) by coniferous forests. Appendix A provides a suggests that the majority of these closed-crown list of wildlife species that are most likely to use stands also originated at the time of European oak woodlands in Lane County, Oregon.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

29 The following species appear to be associated States have found similar results for deer with oak woodlands or some component of (Pearson and Burnett 1940; Forbes et al. 1941; oak-dominated communities and have dis- Sanders 1941; Pearson 1943; Halloran 1943; tributions in Lane County, Oregon. Most of Taylor 1944; Dalke 1947; Dexter et al. 1952; these species may occur in other types of plant Lay 1957; Collins 1961; Duvendeck 1962; Lay communities, but when oaks are present, they 1965). Acorns are a high-energy source of food rely on them. There are other species that and have a strong influence on reproduction, could be considered oak woodland-associated survival, and population levels of deer in a based the definition used for this assessment, given year (Nichol 1938; Forbes et al. 1941; and there would probably be many others Duvendeck 1962). if information on habitat utilization of oak woodlands was available. Sharptail Snake

Deer In part because of its limited distribution, especially in Oregon, the sharptail snake The extent to which deer use oaks can be par- (Contia tenuis) has been designated as “sen- ticularly heavy, and when acorns are available sitive and vulnerable” (SV) by the Oregon during the fall and winter seasons, they are the Department of Fish and Wildlife (Marshall primary food source of the white-tailed deer et al. 1996). Cook (1960) described specific (Odocoileus virginianus) in oak woodlands accounts of the species in California and (Christisen and Korschgen 1955). Menke and Fry Oregon, most in close proximity to oaks. (1980) examined rumen contents of 61 black- Applegarth (1994) suggested that sharptail tailed deer (Odocoileus hemionus columbianus) snakes are found in open oak woodlands in California and found year-round consump- mixed with madrone and chinkapin, with tion of oak browse (twigs and leaves) averaged <40 percent canopy cover and with a grass, 21.5 percent of their diet per month. The high- forb, brush understory, often accompanied est seasonal consumption they found was in the by poison oak. Cook (1960) suggested the summer when oak browse and acorns accounted distribution of sharptail snakes might be for 60 percent of their diet. Acorns alone consti- limited by their specific food preference of tuted 15-20 percent of their diet in the sum- small slugs. In contrast, Applegarth (1994) mer and fall (Menke and Fry 1980). Similarly, suggested that habitat loss of oak/grass monthly consumption of acorns ranged from woodlands due to cattle grazing and conver- 0 percent in June to 62.4 percent in October, sion to Douglas-fir forests have limited the and averaged 25.2 percent per month over a distribution of sharptail snake populations. period of 6 years (Christisen and Korschgen The sharptail snake is considered rare in 1955). Coblentz (1980) found 48 percent of the Lane County (Applegarth 1994). However, stomach contents of four black-tailed deer the BLM oak patch sites sampled are very were comprised of acorns in the Willamette similar to those considered as good sharptail Valley, Oregon. Studies throughout the United snake habitat.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

30 Wild Turkey woodpeckers feed primarily on insects, small vertebrates, wild oaks, fruit, oak buds and Wild turkeys (Meleagris gallopavo) have been flowers, and acorns (Koenig 1980). Koenig introduced in Oregon and are found in oak (1980) stated that stored acorns are often woodlands and oak-conifer habitats. Their diet used year-round, but most importantly in includes seeds, nuts, grains, buds, leaves, arthro- September-March, and MacRoberts and pods, and some vertebrate species, but acorns MacRoberts (1976) suggested acorn wood- are a preferred food in winter when they are pecker winter diets in California consisted available. Wild turkey acorn consumption has almost entirely of acorns. Koenig (1978) and been found to continue throughout all or most Hannon et al. (1987) suggested that popula- of the year in many areas (Christisen and tions and reproduction are limited by the Korschgen 1955; Good and Webb 1940; May et availability of an adequate supply of stored al. 1939; Mosby and Handley 1943). Monthly acorns during the more crucial winter months. percentage of total volume of acorns consumed Similarly, Koenig and Mumme (1987) found ranged from 0.5 percent in September to 73.3 that reproductive success, clutch size, popula- percent in January and averaged 22.7 percent per tion dynamics, and winter survival rates of the month in Missouri (Christisen and Korschgen acorn woodpecker were all determined by 1955). Similar studies reported heavy utiliza- the available supply of stored acorns. Koenig tion of acorns by wild turkeys (Good and (1980) estimated that stored acorns account Webb 1940; Ligon 1946; May et al. 1939; for only about 6-7 percent of the total annual Mosby and Handley 1943). Uhlig and Bailey metabolic requirements of acorn woodpeckers. (1952) suggested wild turkey mortality rates According to Wilson et al. (1991), the dbh were associated with low mast production in of granary trees selected by acorn woodpeckers West Virginia. Smith and Browning (1967) was significantly larger than nongranary trees, found that grass seed was the primary staple and they suggested that acorn woodpecker of wild turkeys in oak woodland chaparral populations are limited by the availability of habitat in California, with acorns being only large >30 inches dbh oaks. They also suggested a secondary source in the fall. They sug- acorn woodpeckers are important as the primary gested that competition for food (from cattle excavators for secondary cavity nesters in oak and other birds), rather than the food source woodlands. Wilson et al. (1991) suggested man- itself, may be a potential limiting factor to agement that maintains large oaks (>20 inches turkeys in California. dbh) to benefit the entire cavity nesting guild.

Acorn Woodpecker Western Gray Squirrel

The acorn woodpecker (Melanerpes formi- Western gray squirrel (Sciurus griseus) distribu- civorus), unlike most other oak woodland tion in Oregon and Washington is mostly in associates, is specifically restricted to habitats conifer-hardwood forests with a strong com- that have some oak component, whether they ponent of Oregon white oak (Cross 1969), are oak woodlands or oak-pine forests. Acorn and the forests they inhabit usually have

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

31 some species of oak present (Asserson 1974; oaks. They predicted that the minimum size Cross 1969; Foster 1992; Gilman 1986). The required for oak stands to support western squirrel is listed as “sensitive-undermined” by gray squirrels was 2-3 acres for short-term the Oregon Department of Fish and Wildlife usage and >5 acres to support long-term (Marshall et al. 1996). Acorns and conifer seeds requirements. are a primary component of their summer-win- ter diet in California, Oregon, and Washington Dusky-Footed Woodrat, Common (Asserson 1974; Barnum 1975; Cross 1969; Foster 1992; Stienecker and Browning 1970), Bushtit, Scrub Jay, White-Breasted but fungi, fruits, buds, and leafy vegetation are Nuthatch, and Mourning Dove also important (Byrne 1979; Foster 1992; Maser Information on these remaining oak wood- et al. 1978; Ryan and Carey 1995a; Stienecker land-associated species, the dusky-footed and Browning 1970). Ryan and Carey (1995b) woodrat (Neotoma fuscipes), common bushtit found western gray squirrels were positively (Psaltriparus minimus), scrub jay (Aphelocoma associated with food-producing shrubs includ- caerulescens), white-breasted nuthatch (Sitta ing snowberry, California hazel, bigleaf maple carolinensis), and mourning dove (Zenaida (Acer macrophyllum), vine maple (Acer circi- macroura), is limited to more generalized group natum), salal (Gaultheria shallon), and black- studies instead of species-specific assessments of berries, and negatively associated with Scotch habitat utilization of oak woodlands. A combi- broom. The high-energy content of mast foods, nation of these studies and information on in addition to their ability to stay fresh when the ecology and habits of each species from stored for use during more critical months the literature was used to categorize them as when other food availability is low, makes them oak woodland associates. a superior food source during some seasons of the year (Stienecker and Browning 1970). Ryan and Carey (1995a) suggested oaks may be the Habitat Components single most important source of food for west- of Oak Woodlands ern gray squirrels; however, annual mast pro- duction by oak species can be highly variable Food (Beck 1993) and acorns are an unpredictable source of food for wildlife. Western gray squir- Acorns are an important high-energy food rels must rely on other foods, including seeds, resource to many wildlife species in oak buds, and stems from other trees; fungi; and woodlands (Block et al. 1990; Pavlik et al. forbs during years when the acorn crop is low 1991; Kerns 1980; Goodrum et al. 1971; or has failed (Ryan and Carey 1995a). Ryan and Christisen and Korschgen 1955; Martin et Carey (1995a) suggested two of the most limit- al. 1951). Acorns are an important seasonal ing factors of western gray squirrel abundance source of energy prior to the harsh winter are the availability of oak-dominated habitats months when other foods are less abundant and the availability of mast, and they suggested or nutritious (Block et al. 1990), and are that management for western gray squirrels used year-round by some species that cache include a minimum of 18 ft 2 basal area of the surplus (Goodrum 1940; Good and

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

32 Webb 1940). Christisen and Korschgen (1955) Oak foliage and plant species associated with listed deer, turkeys, quail, ducks, and crows as oaks are another important food source to species that rely heavily on acorns for food dur- wildlife in oak woodlands. Kerns (1980) found ing parts of the year. Some experts suggested wildlife species diversity and abundance was that at least 37 species of terrestrial mammals associated with the density of understory and 30 birds eat acorns in oak woodlands in plants in northern California oak habitats. California (Block et al. 1990). Acorn avail- Block et al. (1990) suggested that the majority ability is important for the survival, repro- of wildlife in California oak habitats depend ductive success, and population size of many on the fruit from plants associated with oak oak woodland species (Forbes et al. 1941; woodlands. Some of the more common fruit Linduska 1950; Burns et al. 1954; Uhlig 1956; bearing shrubs in California oak woodlands Duvendeck 1962). Van Dersal (1940) suggest- include: redberry (Rhamnus crocea), coffee- ed that the distribution of some wildlife spe- berry (R. californicus), buckbrush (Ceanothus cies may be associated with the range of oak cuneatus), toyon (Heteromeles arbutifolia) and habitat, and Coblentz (1980) suggested that mistletoe (Phoradendron spp.) (Block et al. acorn loss by oak removal would have detri- 1990; Block and Morrison 1991). Manzanita mental effects on local populations of some and mistletoe and other species of Ceanothus species in the Willamette Valley. Goodrum et may provide food resources for animals in al. (1971) suggested that freezing tempera- Oregon oak woodlands. Kerns (1980) com- tures resulted in acorn crop failure during 1 pared mature oak, mixed oak-conifer, young year of their study, and Sharp and Sprague oak, and oak conifer edge habitats in northern (1967) found 4 years with total crop failure California and found that the mature oak and partial crop failure in 4 other years over a habitats with dense understory of shrubs and 50-year period due to freezing temperatures. grasses were highest for species diversity and In addition to weather, Block et al. (1990) abundance of wildlife. Kerns suggested that the listed genetics, nutrition, close proximity to fruit, seeds, stems, and leaves from shrubs, other trees causing root crowding and shading, combined with the niche created by the verti- soil conditions, and physiographical features cal edge between the shrub layer and the as variables that may affect acorn production. mature oak canopy, produce desirable habitat The negative impact of acorn crop failure on for a variety of wildlife species. some wildlife populations can be devastating. For example, Christisen and Korschgen (1955) Cover suggested that there was a direct correlation with gray squirrel abundance and the abun- According to Ingles (1965), Barrett et al. dance of acorns, and population levels of gray (1976), and Pavlik et al. (1991), oaks provide squirrels, bears, pigs, and deer may be limited an important source of cover from exposure by the annual crop of acorn mast (Goodrum for mammals in California. The combination 1940; Duvendeck 1962; Piekielek and Burton of trees and shrubs in oak woodlands provides 1975; Barrett 1978). a vertical structure that helps conceal mammal

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

33 den sites and prey from predators and provides parks in Northern California: Redwood National habitat for many shrub nesting bird species Park and Annadel State Park. Literature on (Pavlik et al. 1991). Leaf litter, grass and forb similar restoration studies in oak woodlands cover, and coarse woody debris are important of the Pacific Northwest was not located at cover variables to herpetofauna in California oak the time of this review. woodlands (Block and Morrison 1998). Cavities in standing or fallen oak trees and snags are used Oak woodlands in Redwood National Park are for nesting, estivation, and protection from pred- known as bald hills oak woodlands, which are ators by many amphibian and reptile species; in characterized by a patchy mosaic of oak- and addition, there is a diverse community of bird grass-dominated areas (Reed and Sugihara species that nest in oak canopies and others that 1987). Suppression of frequent fires (both nat- rely on cavities for nesting (Pavlik et al. 1991). ural and those set by Native Americans) is Verner (1983) suggested that oak woodlands believed to have led to increased oak densities were among the top three habitat types in North since the 1850’s (Reed and Sugihara 1987), America for breeding bird diversity. Hagar and forming more even-aged stands and more nar- Stern (1997) found more neotropical migrants row-crowned trees. Douglas-fir encroachment breeding in oak woodlands in the Willamette has noticeably decreased the extent of prairie Valley than others have found in Douglas-fir and oak woodland (Sugihara and Reed 1987b). forests in western Oregon (Carey et al. 1991; In order to achieve the park’s goals of manag- McGarigal and McComb 1992), and many of ing and restoring these oak woodlands, vari- the more common resident species they found ous prescribed burns have been carried out were rare or absent from closed canopy Douglas- (Sugihara and Reed 1987a, 1987b). When fir forests. Wilson et al. (1991) found 6 of the 10 sufficient fuels occurred in areas to be most abundant breeding birds in California oak burned, low-intensity backing and head fires woodlands were cavity nesters. Cavity nesters killed nearly all Douglas-firs <9 feet and larger comprised 25 percent of the breeding species Douglas-firs that were very scorched (70 per- and more than 58 percent of the total individu- cent scorching of trees or greater) (Sugihara als breeding in their study, which they suggested and Reed 1987b). These fires also top-killed is higher than densities of most other bird com- most oaks <9 feet; however, these individuals munities in temperate regions. sprouted back in the following years. Larger oaks, >9 feet, were generally unharmed and also produced basal sprouts following the fires. Restoration Less intense fires (fires remaining in the and Management understory) were unable to kill trees >9 feet. Literature Review Sugihara and Reed (1987a) concluded that in order to successfully control Douglas-fir growth, fire frequency would need to occur Conifer Encroachment at least every 10 years. They have also sug- Intensive efforts to restore Oregon white oak gested that creating a multiaged stand of oaks, woodlands have been conducted at two public typical of pre-European settlement in this area,

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

34 would require low-intensity fire at intervals Hastings et al. (1997) reported that Douglas- of approximately 5 years. In the bald hills of firs receiving the herbicide treatments were Redwood National Park, regular low-inten- killed; however, recruitment of this species sity fires would likely decrease the damage continued in areas where large trees were left to canopy trees while lowering the constant standing and numerous smaller felled trees regeneration from previous fires. In addition, were able to sprout from stumps left too high. sustained burning may restore other native Additional cuts without herbicide were effec- vegetation adapted to frequent fires. tive; however, some trees >12 inches dbh sur- vived, likely due to shallow cuts. Sugihara and Reed (1987a) have also recom- mended combining prescribed burning with Prescribed burning was effective in decreas- manual removal and/or girdling of larger inva- ing the number of Douglas-fir seedlings per sive trees that will not be effectively controlled acre by 50 percent, while Oregon white oak by fire. Girdled trees may also provide snags seedlings increased by 9 percent. Areas of for wildlife species. native California fescue grasses (Festuca cali- fornica) burned with high intensity, while Studies and work conducted at Annadel State areas with less surface fuels permitted survival Park in the Sonoma Mountains of California of Douglas-fir seedlings. have focused on describing the causes of Douglas-fir invasion and restoration strategies Because prescribed burning is not effective in for oak woodlands at this park (Barnhart et all areas, current management strategies at this al. 1987; Barnhart et al. 1996; Hastings et al. park include using a combination of burning 1997). and manual removal of seedlings where burn- ing is not as effective (Hastings et al. 1997). Restoration work of oak woodlands at Annadel State Park has included both manual removal of Douglas-fir and prescribed burning of por- Thinning of tions of the park (Hastings et al. 1997). Initial Closed-Canopy Stands efforts included a combination of prescribed burning in “high priority areas” along with McDonald and Ritchie (1994) have suggested two cutting treatments for Douglas-fir trees that thinning of California black oak stands >6 inches dbh: 1) application of glyphosate to may be beneficial for wildlife by allowing trees shallow cuts in the cambium layer of larger to produce larger crowns, leading to increased Douglas-firs, and 2) felling of smaller trees, acorn production. However, they point out which added fuel for burn areas. Trained vol- that thinning of this species often results in unteers later repeated manual removal using the formation of epicormic branches that yield the frill cuts without herbicide treatment. no acorns. These small subcrown branches are Additional prescribed burns were conducted in produced by less vigorous trees often occur- larger areas (95-242 acres) and monitored to ring in closed canopy stands. McDonald and assess survival and regeneration. Ritchie suggest that a series of thinnings will

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

35 allow the trees to gradually increase in vigor, they suggest that the availability of acorns may and thus crown size, and reduce the rate of be more continuous in oak woodlands if two epicormic branching. broad age classes of trees (0-80 and 81-120+ years) are maintained. Because mast produc- Tappeiner and McDonald (1980) note that for tion often varies among trees at individual California black oak, although acorn production sites (Beck 1993), identifying and retaining generally increases after 80 years, the incidence better producing trees may also increase the of heart rot also increases at this time. Therefore availability of acorns for wildlife.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

36 SUMMARYSUMMARY AND AND RECOMMENDATIONSRECOMMENDATIONS

Vegetation Patterns microclimate and soil moisture. Oak trees tended to be most highly aggregated on xeric, The vegetation structure and spatial distribution south- or southwest-facing hill slopes or ridges of oaks is highly variable among the 13 BLM that were less favorable to conifer reproduc- sites surveyed. From a landscape perspective, all tion. On the most extreme sites, even oaks of the sites represented small patches of oaks are infrequent and the sites are dominated by (median area = 2 acres) imbedded in a hetero- grass or shrubs. It remains unclear whether geneous mosaic of conifer stands, clearcuts, oaks will eventually infiltrate these meadows and non-forested areas. However, some BLM and dominate the site; it may be that these sites (e.g., Cougar Mountain, Gilkey Creek, Sears areas are so prone to drought that tree estab- Road) represented only a portion of a larger oak- lishment is unlikely to ever occur. In general, conifer woodland extending outside of the oak regeneration was not abundant and most surveyed patch boundaries. The relatively commonly observed in areas where light levels small patches of oaks delineated do not ade- were relatively high; i.e., meadows and light quately represent the structural or composition- gaps in woodland-type patches. Most of this al richness of the plant communities observed regeneration was vegetative sprouting, which at the BLM sites. The spatial distribution of oaks formed the clusters of shrub-form oaks charac- often appeared to be influenced by environmen- teristic of meadow-type patches. Live oak trees tal gradients (i.e., soil moisture, aspect), and rarely were observed to have crowns in domi- oak trees were frequently interspersed among nant canopy positions on mesic sites, although conifers and other hardwood species. Oaks that decadent oaks interspersed among conifers or are able to persist among conifers in canopy gaps big-leaf maples occurred at a few sites. or along stand edges provided a unique structural component in the vertical stratification of these These observations may indicate that most of stands. Arboreal lichens, other epiphytes, and the BLM sites situated on xeric, mid- to upper- nonvascular plants associated with oaks are likely slope positions are likely to have oak trees in to increase the plant species diversity at the BLM dominant or codominant canopy positions, sites to a much greater extent than the presence regardless of fire suppression (assuming no of oak as a single tree species would indicate. tree harvest). However, there is evidence (e.g., oak snags under conifer canopies, Douglas-fir Much of the variation in oak distribution seedlings/saplings under oaks) that Douglas- observed on the BLM sites appears to be influ- fir are becoming more abundant on mesic enced by interactions among aspect, slope sites and dominating stands that had been position, and soil characteristics that influence oak-conifer woodlands and savannas. Based

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

37 on these observations at the BLM sites and available to fully examine the variation a review of vegetation studies conducted of forest composition prior to European in the Willamette Valley and foothills of the settlement, the 1850’s surveys suggest Cascades, it appears that the cessation of peren- that much of the McKenzie and South nial fires by Native Americans and active fire Valley Resource Areas were mixed suppression has promoted conifer succession on stands of Douglas-fir, ponderosa pine, all but the driest sites. and Oregon white oak.

Vegetation maps of Lane County constructed ❖ The importance of meadows, canopy from surveys performed in the 1850’s indicate gaps, and rocky balds should be recog- that the BLM McKenzie and South Valley nized: these relatively small openings Resource Areas were a heterogeneous land- are relatively undisturbed (compared scape of Douglas-fir forest, mixed conifer- to adjacent pastures and clearcuts) and hardwood forest, Oregon white oak-ponderosa may be important strongholds for native, pine forest, mixed species savanna, and prairie. early seral plants, reptiles, and small Most of the BLM sites surveyed appear to mammals. have been closed-canopy forest or woodland plant communities at the time of European To help determine possible management or settlement in this area (Table 13). However, restoration actions, the 13 surveyed sites were notes from the historic surveys suggest that classified into three groups based on site char- tree densities were lower and average tree acteristics and the degree of oak-conifer com- diameter in these stands may have been petition observed (Table 14): greater than the 1998 estimates. Retrospective studies (Johannessen et al. 1971; Cole 1977) ❖ Xeric: Dry sites on ridges or steep, and the 1850’s surveys also indicate that pon- south-to-southwest hill slopes have lim- derosa pine was commonly associated with ited oak size and conifer growth in these oaks in this area and probably much more sites, which have likely undergone the extensively distributed in the Willamette least amount of change in community Valley foothills than it is today. structure post-European settlement.

Some federal planners and ecologists have ❖ Mesic: Lower slopes and increased patch recommended that natural forests serve as a cover by more mesic soils in these sites reference to guide desired composition and have provided more favorable growing structure of forest reserves (Dombeck 1996; conditions and thus greater and more Thomas 1996; Swanson et al. 1997). If oak rapid changes in canopy composition woodlands such as those surveyed are to be over time relative to xeric sites. managed in this way: ❖ Wet: Sites occurring on low slopes ❖ The diversity of tree species should be where mesic and seasonally wet soils sustained: although there is no data covered >50 percent of the patch area

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

38 have undergone the most dramatic and mixed conifer stands have developed to changes in canopy composition. Within cover the majority of these formerly more the last 150 years, closed-canopy oak open areas.

Table 13. Historical vegetation classifications for the surveyed sites. Classifications are taken from GIS maps created from interpretative data of Christy et al. (1996, 1997). A dashed line in the table indicates that information was not available for that location.

Site Major Vegetation Classification Specific Vegetation Classification

Anthony Creek Closed forest upland - Bates Woodland Scattering or thinly timbered Douglas-fir/white oak (bigleaf maple) woodland, with brushy undergrowth of hazel, other shrubs, oak brush, oak stump sprouts,young Douglas-fir, bracken, briars, and sometimes willow. Cougar Mountain Prairie, closed forest upland - Eagle's Nest - - Fox Hollow - Mixture of 1) xeric Douglas-fir/Chinquapin-madrone forest on south slopes 2) mesic Douglas-fir/bigleaf maple forest on north slopes and bottoms, sometimes with incense cedar, oak, grand fir, red cedar, yew, red alder and dogwood. Gilkey Creek Closed forest upland bordering Bordering areas: Oregon white oak/Douglas-fir/ponderosa pine savanna and prairie savanna and white oak/ponderosa pine savanna. Kloster Mountain - - Rattlesnake Butte Woodland and closed forest upland - Sears Road Prairie - Seventy-Ninth Closed forest upland - Weiss Road Woodland Scattering or thinly timbered Douglas-fir/white oak (bigleaf maple) woodland, with brushy undergrowth of hazel, other shrubs, oak brush, oak stump sprouts, young Douglas-fir, bracken, briars, and sometimes willow.

Wendling - Mixture of 1) xeric Douglas-fir/Chinquapin-madrone forest on south slopes 2) mesic Douglas-fir/bigleaf maple forest on north slopes and bottoms, sometimes with incense cedar, oak, grand fir, red cedar, yew, red alder and dogwood. Wills Road Woodland and - closed forest upland -

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

39 Table 14. Classification of surveyed sites based on site characteristics, degree of conifer competition, and possible management actions.

Site Groupings Environmental Conditions and Oak Possible Ecosystem Management Growth and Distribution Characteristics or Restoration Actions (M =meadow community type; W =woodland community type)

Xeric Anthony Creek (M) - dry, steep slopes - protect meadows by controlling increase of nonnative plant cover Bates (could also be in mesic group) (M) - low soil moisture levels - monitor and eliminate future conifer Kloster Mountain (M) - oaks typically shrubby and short (< 40 feet) encroachment with thin stems

Mesic Fox Hollow (W) (could also be in - medium slopes - sustain and/or restore diversity of wet group) - low to medium soil moisture levels tree species, particularly ponderosa pine Gilkey Creek (M) - open areas with small shrubby or stunted and Oregon white oak Rattlesnake (M) oaks - control nonnative plants Seventy-Ninth (M) - woodland areas with larger oaks (30-60 - historic vegetation classifications Wendling (M) feet) typically overtopped by conifers to may provide reference conditions Weiss Road (M some degree - possible silvicultural methods include thinning of conifers and smaller oaks; snag creation

Wet Cougar Mountain (W) - restoration of open woodlands, prairie, Eagle’s Rest (W) - low slope areas savanna will require intensive, susained Sears Road (W) - medium to high seasonal soil moisture levels efforts Wills Road (W) - large (60-80 feet) forest form oaks; only a - eliminate/control abundant nonnative few older open grown trees with conifer plants encroachment very evident - silvicultural treatments may include selective thinning of oaks and conifers; prescribed burning; snag creation

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

40 very crude estimates based on a different oak Wildlife Habitat species from a different part of the country, the estimates may be high rather than low Mast Production because they don’t account for the percent- age of trees that don’t produce acorns and Goodrum et al. (1971) studied the relation- the cyclic nature of mast production. In the ship between acorn production and tree char- Willamette Valley, mast years have occurred acteristics of seven oak species in Texas and very infrequently in the last 15 years (David Louisiana. He found acorn yields generally Hibbs personal communication). Goodrum et increased with age, bole diameter, and crown al. (1971) also suggested that tree size posi- size of the tree. Similarly, Christisen and tively influenced the percentage of trees that Korschgen (1955) found a strong association produced acorns, and an important limiting between crown size and acorn production. factor of acorn production can be freezing In contrast, Cypert (1951) suggested radial winter temperatures. Verner (1980) suggested growth rate rather than tree size was the most managing oak woodlands for wildlife should important factor determining the size of the include a minimum of 100 pounds of acorns acorn crop. The BLM oak patches were not per acre, which exceeds the approximated directly samples for acorn production because acorn yield for 70 percent of the oak patches of time and logistic constraints; however, sampled. Therefore it appears that only the expected acorn yields for white oak (Q. alba) Cougar Mountain, Eagle’s Rest, Gilkey from Goodrum et al. (1971) were used to cal- Creek, Sears Road, and Wills Road sites might culate acorn potential production rates using be capable of producing a significant abun- tree dimensions from the BLM oak patches. dance of acorns available for wildlife. Potential acorn yield based on numbers of oak trees in acorn producing size classes from each of the BLM patches ranged from 0 to 1,333 total Vegetation pounds per oak patch (mean = 195 pounds), and from 0 to 494 pounds of acorns per acre Average shrub coverage ranged from 24 to 65 (mean = 89 pounds) (Table 15). Sixteen of percent in nine oak woodland sites in the 25 oak patch sites were predicted to yield Willamette Valley (Hagar and Stern 1997). less than 50 pounds/acre of acorns, includ- Poison oak was the dominant shrub species in ing 10 that were predicted to have less than four of their sites, and Franklin and Dyrness 10 pounds/acre. The four highest yields were (1988) stated it to be the dominant shrub >250 pounds/acre. The reason the estimated species in most oak woodlands in Oregon and yields were lower than might be expected given Washington. Similarly, poison oak dominated the number of trees in some of the oak patches the understory vegetation in the oak patches is that most of the oaks were <15 inches sampled. In addition, there was a high frequency dbh, which is at the smaller end of the size of nonnative plant occurrence (Table 10). found to produce acorns by Goodrum et al. However, in contrast to Hagar and Stern (1997), (1971). Although these expected yields are coverage of other shrub species important to

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

41 Table 15. Estimated annual acorn yields for the surveyed patches. Yields were approximated using data from Goodrum et al. (1971; Table 2) and estimated numbers of oak trees in acorn-producing size classes.

Total Estimated Estimated Patch Area Acorn Yield Acorn Yield Patch (acres) (pounds) (pounds/acre)

ANTH-1 1 5.0 5.0 ANTH-2 2 5.0 2.5 ANTH-3 2 5.0 2.5 BATES 3 15.0 5.0 COUG-1 2 550.0 275.0 COUG-2 2 290.0 145.0 EAGL-1 1 495.0 495.0 EAGL-2 2 790.0 395.0 FOX 2 110.0 55.0 GILK-1 2 275.0 135.0 GILK-2 1 35.0 35.0 GILK-3 2 165.0 80.0 KLOS-1 3 5.0 2.5 KLOS-2 3 5.0 2.5 KLOS-3 5 0.0 0.0 KLOS-4 3 15.0 5.0 RATT-1 4 100.0 25.0 RATT-2 3 60.0 20.0 RATT-3 4 90.0 20.0 SEARS 5 1,330.0 265.0 SEVENT 2 35.0 15.0 WEISS 3 150.0 50.0 WEND-1 2 15.0 7.5 WEND-2 3 0.0 0.0 WILLS 2 330.0 165.0

Mean 195.0 88.3

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

42 wildlife is much less frequent in the BLM trees and snags >20 inches dbh located were on oak patches, and many that were common in only 40 percent of the sites. Consequently, the their study are rare or absent, including; service value of the majority of the oak patch sites to berry (Amelanchier alnifolia), ootka rose (Rosa cavity nesting species, especially those associ- nutkana), and snowberry. Thilenius suggested ated with larger diameter trees and snags, is poor. that previously grazed areas favor poison oak Hagar and Stern (1997) suggested that the growth because cattle often avoided it, giving it most limiting factor in the semiopen oak a competitive advantage over other more palat- woodlands might be large-diameter oaks for able shrub species, and according to Longhurst cavity nesting species. Although there were et al. (1979), browsing by livestock and deer more snags in the smaller size classes found, may be the primary factor impacting regenera- again the majority of these were concentrated in tion of oaks in California rangelands. Mellanby a few sites. Over 50 percent of all the snags were (1968), Griffin (1971), and Block et al. (1990) found on four sites, and over 96 percent were suggested that extensive forging on shrubs found on just 48 percent of the sites. There were and oak seedlings can kill or prevent some plants no oak snags found in 68 percent of the oak from regenerating. Grazing by wildlife, well- patch sites. Based on availability of large- and drained soils, shading from bordering conifer medium-sized snags, it appears that seven of forests, and small patch sizes, probably all con- the oak patch sites should provide ample tribute to the invasion of nonnative plants and opportunities for cavity nesting species. high densities of poison oak. Patch Size Cavities Probably the most limiting factor of the oak The importance of cavities to wildlife in oak patch sites, in terms of quality of oak woodland woodlands was discussed earlier. Hagar and habitat, is their size. Wilson et al. (1991) sug- Stern (1997) suggested that large-diameter white gested 50-100 hectares (= ~123-247 acres) as oak trees grown in open areas in Oregon usual- the minimum size of management areas for oak ly produce a greater number of cavities than woodlands. These sites would not need to be that the same diameter class would in Douglas-fir large to support populations of some oak wood- forests, and they found three cavity nesters in land associated species; however, they would their study were positively correlated with need to be substantially larger than these patches tree diameter. Similarly, five cavity nesters are. Sisk et al. (1997) reported that composition and one open nester were positively associat- of avian communities in small oak woodland ed with the abundance of large-diameter trees patches (<3 hectares) in California were pri- (>20 inches dbh) and the abundance of cavi- marily driven by the assemblage of birds in the ties (Wilson et al. 1991). There were only 4 surrounding matrix rather than intrinsic habitat total oak snags >20 inches dbh and 27 conifer characteristics of the oak patches. An Effective snags found among all 13 BLM study sites. In Area Model (EAM) proposed by Sisk et al. addition, there were less than 10 live oaks >20 (1997) predicts that the influence of matrix on inches dbh found at the sites. All the live large avian community diversity decreases as the ratio

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

43 of patch interior to perimeter length decreases. bird species should include the maintenance Although these data are from oak (species of large tracts of woodland with minimal unknown) woodlands in southern California, edge influence. In addition, a diversity of stand the results suggest that the BLM sites may be structures will support a diversity of bird spe- too small to support bird communities that cies, but species using large-diameter oaks in are significantly different than the surrounding semi-open woodlands are perhaps the most conifer forest. limited, and should therefore should receive priority consideration in conservation planning.” Oak Management Verner (1980) recommends the following for birds: “Maintain mixed-species, uneven-aged Recommendations stands, especially allowing for live oak reten- tion; Provide a continuing supply of oaks, by Other Authors generally distributed on every 1- or 2-acre Applegarth (1994) included specific recom- parcel of the management unit that presently mendations for ecosystem management in supports oaks; Provide a continuing supply of areas where the sharptail snake is found: “A) large, old trees, especially those with a good Discourage Douglas-fir trees from replacing record of high acorn production; Manage for a the grass/oak community; in the case of a mean annual acorn production of at least 100 timber sale, leave a ‘no-replant’ buffer of at pounds per acre; Provide an ample shrub layer least one tree height (50 meters) on all sides of where one occurs in existing oak stands, and the identified habitat. B) Seems best not to consider the possibility of establishing shrubs burn identified habitat and probably best not in stands from which they were removed in to burn the ‘no-replant’ buffer. C) Do not com- the past; Consider needs of oak-using species pact the soil; do not permit grazing of livestock from different, adjacent habitat types.” within forested habitat; do not drive, build Ryan and Carey (1995a) recommend that roads, or locate skid trails through identified management guidelines for oak woodlands habitat. D) Do not flood or poison habitat.” in Puget Trough should include the follow- According to Barrett (1980), wildlife biologists ing: “To maximize wildlife use, maintain or recommend the following for management of develop corridors to link habitat fragments oak dependent wildlife: “1) maintain a 25 to 50 and minimize the adverse impacts of frag- percent canopy cover of oaks, 2) maintain a basal menting the landscape; Retain adjacent stands area of 200 to 2000 ft2 per each 40 acres, of conifers and hardwoods; Maintain canopy 3) maintain a mixture of age classes including cover of 40 to 60 percent; Maintain tree spe- older, more prolific seeders, and 4) disperse cies composition at 25-75 percent oak, 25-75 oaks in 0.5-5.0-acre aggregations.” percent Douglas-fir, and 10-20 percent other hardwoods; Preserve a near mix of snags, dead Hagar and Stern (1997) conclude, “Conservation and downed trees, seed trees and den trees; strategies for oak woodlands and their associated Kill overtopping Douglas-fir to allow oaks to assemblages of neotropical-migrant and resident grow to an open form (girdle the Douglas-firs

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

44 for snag management or fall them to provide mast production, vertical diversity, and recruit- coarse woody debris); Thin oak or Douglas- ment (Bleier et al. 1993); Plan periodic burns fir/oak stands to reduce over crowding and of the grass and shrub layer to stimulate young water stress and allow remaining oaks to shoot growth, prevent dense shrub competition become larger, more vigorous, more productive, (particularly Scotch broom), and maintain tree and more fire resistant; Remove smaller Douglas- spacing (Columbia Gorge Audubon Society fir trees under the oak canopy that are compet- 1990).; Maintain an open to patchy under- ing with oaks for water and that will eventually story with a high level of vegetation diversity; overtop the oaks; Retain old-growth Douglas Minimize human disturbance such as excessive fir within oak stands; Maintain a mix of age and trails and roads which accelerate root damage to size classes of hardwoods to provide sustained oaks and invasion of weedy species.”

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

45

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57

APPENDIXA P P E N D I X A A

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

59 List of Wildlife Species Potentially Occurring in the Habitats Found in the Surveyed Sites

Brown

Habitats

Species Dry hillside/ grass forb Deciduois- hardwood Conifer- forest hardwood Shrub-forest edge Grass-forest edge

clouded salamander 1 2 1 x ensatina 1 1 1 western redback salamander 2 2 northern alligator lizard 1 1 2 2 southern alligator lizard 1 1 2 2 x western fence lizard 1 2 1 2 western skink 1 1 1 rubber boa 1 1 racer 1 1 1 1 sharptail snake 1 1 1 2 ringneck snake 2 1 1 x/pine gopher snake 1 1 2

western terrestrial garter snake 2 1 1 2

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only used old-growth, no score was given.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

60 List of Wildlife Species Potentially Occurring in the Habitats Found in the Surveyed Sites

Hagar 1985 1 Csuti and et al. Stern Snags Cavities 1995 2 1977 3 Grass-forb Grass-forb hills Deciduous- hardwoods Coniferous hardwoods Suggested dbh (inches) Minimum tree height (feet Oak 50 birds Top clouded salamander 1 2 1 x ensatina 1 1 1 western redback salamander 2 2 northern alligator lizard 1 1 2 2 southern alligator lizard 1 1 2 2 x western fence lizard 1 2 1 2 western skink 1 1 1 rubber boa 1 1 racer 1 1 1 1 sharptail snake 1 1 1 2 ringneck snake 2 1 1 x/pine gopher snake 1 1 2 western terrestrial garter snake 2 1 1 2

2 Species use of oak habitat 3 The 50 most frequent bird species observed in 9 oak woodland sites in the Willamette Valley, Oregon, 1994-1996. Numbers refer to ranking in abundance (1-50).

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

61 Brown

Habitats

Species Dry hillside/ grass forb Deciduois- hardwood Conifer- forest hardwood Shrub-forest edge Grass-forest edge northwestern garter snake 2 2 2 2 1 common garter snake 1 1 western rattlesnake 1 2 2 turkey vulture 2 2 2 x x x black-shouldered kite 2 1 sharp-shinned hawk 1 x x Cooper’s hawk 1 1 x x x northern goshawk 2 x x x red-tailed hawk 1 1 2 2 x x 45 American kestrel 1 2 1 1 x x 17 20 ring-neck pheasant 2 2 2 2 blue grouse 2 2 1 1 ruffed grouse 1 1 1 1 48 wild turkey 1 2 2 x California quail 1 1 2 x mountain quail 2 1 2 2 2

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only used old-growth, no score was given.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

62 sharp-shinned hawk sharp-shinned kite black-shouldered wild turkey wild grouse ruffed grouse blue pheasant ring-neck kestrel American hawk red-tailed hawkCooper’s vulture turkey rattlesnake western snake garter common snake garter northwestern northern goshawk northern mountain quail mountain quail California 2 2 1 2 2 1

2 1 1 2 2 1 1 1 2 2 1 2 1 1 1 1 2 2 2 1 1 2 2 1 2 2 2 2 1 1 1 2 2 2 2 1 2 1 1 2 1 2 1 2 1994-1996. Numbers refer to ranking in abundance (1-50). abundance in ranking to refer 1994-1996.Numbers 3 2 1985

The 50 most frequent bird species observed in 9 oak woodland sites in the Willamettein sites Valley,woodland oak 9 in observed species bird frequent Oregon,most 50 The habitat oak of use Species AK OODLAND RESOURCES IN BLM’S EUGENE DISTRICT C I R T S I D E N E G U E S ’ M L B N I S E C R U O S E R D N A L D O WO K OA F O T N E M S S E S S A

1 x x x

Grass-forb hills Snags x x x x x Deciduous-

hardwoods

Coniferous x x x x x

hardwoods 17 63 Suggested dbh

(inches) Cavities

20 Minimum tree

height (feet 1995 Csuti et al. et x x x x

Oak

2 1977 Hagar Stern and 48 45

Top 50 birds

3 Brown

Habitats

Species Dry hillside/ grass forb Deciduois- hardwood Conifer- forest hardwood Shrub-forest edge Grass-forest edge band-tailed pigeon 1 1 1 1 x 46 mourning dove 1 1 2 1 x 37 common barn owl 2 2 1 1 x x 25 20 x western screech owl 1 2 1 1 x x 17 20 x great horn owl 1 1 1 1 x x x 25 30 northern pygmy owl 2 1 1 1 x x 17 30 barred owl 2 1 x 25 30 northern saw-whet owl 2 2 1 1 x x 17 20 common nighthawk 1 1 1 1 1 common poorwill 1 1 2 2 x Vaux’s swift 2 2 1 1 x x 25 40 Anna’s hummingbird 1 1 2 rufous hummingbird 1 1 1 1 38 acorn woodpecker 1 2 2 1 x x 17 30 x 50 red-breasted sapsucker 2 2 2 2 x x 15 20 33 northern flicker 1 1 2 1 x x 17 10 34

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only used old-growth, no score was given.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

64 common barn owl barn common dove mourning pigeon band-tailed western screech owl screech western northern pygmy owl pygmy northern owl horn great barred owl barred northern saw-whet owl saw-whet northern common poorwill common nighthawk common Vaux’sswift acorn woodpecker acorn hummingbird rufous hummingbird Anna’s red-breasted sapsucker red-breasted northern flicker northern 1 1

2 1 1 1 2 1 2 2 1 1 2 1 1 1 2 1 2 1 1 2 1 1 1 2 1 2 2 1 2 1 1 2 1 1 1 1 1 2 1 1 2 1 1 2 2 1 1 1 1 1 1 1 2 1 1 1 1 2 2 1 1994-1996. Numbers refer to ranking in abundance (1-50). abundance in ranking to refer 1994-1996.Numbers 3 2 1985

The 50 most frequent bird species observed in 9 oak woodland sites in the Willamettein sites Valley,woodland oak 9 in observed species bird frequent Oregon,most 50 The habitat oak of use Species AK OODLAND RESOURCES IN BLM’S EUGENE DISTRICT C I R T S I D E N E G U E S ’ M L B N I S E C R U O S E R D N A L D O WO K OA F O T N E M S S E S S A

1 x

Grass-forb hills

Deciduous- Snags x x x x x x x x x

hardwoods

Coniferous x x x x x x x x x x

hardwoods 65 25 17 25 17 25 17 25 17 15 17 Suggested dbh

(inches) Cavities 20 20 30 30 30 20 40 30 20 10 Minimum tree

height (feet 1995 Csuti et al. et x x x x x x

Oak

2 1977 Hagar Stern and 37 46 38 50 33 34

Top 50 birds

3 Brown

Habitats

Species Dry hillside/ grass forb Deciduois- hardwood Conifer- forest hardwood Shrub-forest edge Grass-forest edge downy woodpecker 1 2 x x 11 10 28 hairy woodpecker 2 x 15 20 41 olive-sided flycatcher 1 2 2 x x western wood pewee 1 1 1 x 2 willow flycatcher 2 1 49 Hammond’s flycatcher 2 1 1 western kingbird 2 2 1 x x horned lark 1 purple martin 2 2 1 1 15 10 tree swallow 2 2 x x 15 20 36 violet-green swallow 1 2 x x 15 20 Stellar’s jay 2 1 2 2 31 scrub jay 1 2 1 2 x 23 American crow 1 2 2 2 44 common raven 1 1 2 2 black-capped chickadee 1 1 1 x x 9 10 4

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only used old-growth, no score was given.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

66 downy woodpecker downy hairy woodpecker hairy western kingbird western flycatcher Hammond’s flycatcher willow western wood pewee wood western flycatcher olive-sided tree swallow tree martin purple violet-green swallow violet-green lark horned black-capped chickadee black-capped ravencommon crow American jay scrub jay Stellar’s 1

1 2 2 1 2 2 1 1 1 1 1 2 2 2 2 1 1 2 2 2 1 1 2 2 1 2 1 2 1 1 2 2 1 2 1 1 1 1 2 1 2 2 2 2 1994-1996. Numbers refer to ranking in abundance (1-50). abundance in ranking to refer 1994-1996.Numbers 3 2 1985

The 50 most frequent bird species observed in 9 oak woodland sites in the Willamettein sites Valley,woodland oak 9 in observed species bird frequent Oregon,most 50 The habitat oak of use Species AK OODLAND RESOURCES IN BLM’S EUGENE DISTRICT C I R T S I D E N E G U E S ’ M L B N I S E C R U O S E R D N A L D O WO K OA F O T N E M S S E S S A

1

Grass-forb hills

Deciduous- Snags x x x x x x

hardwoods

Coniferous x x x x x x

hardwoods 67 11 15 15 15 15 Suggested dbh 9

(inches) Cavities 10 20 10 20 10 20 Minimum tree

height (feet 1995 Csuti et al. et x x x

Oak

2 1977 Hagar Stern and 28 49 41 36 23 44 31 2 4

Top 50 birds

3 Brown

Habitats

Species Dry hillside/ grass forb Deciduois- hardwood Conifer- forest hardwood Shrub-forest edge Grass-forest edge chestnut-backed chickadee 2 1 x x 9 10 43 bushtit 1 2 1 39 red-breasted nuthatch 1 x x 17 20 24 white-breasted nuthatch 1 1 x x 17 20 x 17 brown creeper 2 1 x x 15 20 13 Bewick’s wren 1 2 1 x 15 house wren 1 1 x 15 10 x 6 winter wren 1 1 x 30 golden-crowned kinglet 2 western bluebird 1 1 1 1 x 15 10 x Townsend’s solitaire 1 1 2 Swainson’s thrush 2 2 1 2 7 hermit thrush 1 1 2 American robin 1 1 1 1 x 5 varied thrush 1 1 2 wrentit 1 1 x

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only used old-growth, no score was given.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

68 Hagar 1985 1 Csuti and et al. Stern Snags Cavities 1995 2 1977 3 Grass-forb Grass-forb hills Deciduous- hardwoods Coniferous hardwoods Suggested dbh (inches) Minimum tree height (feet Oak 50 birds Top chestnut-backed chickadee 2 1 x x 9 10 43 bushtit 1 2 1 39 red-breasted nuthatch 1 x x 17 20 24 white-breasted nuthatch 1 1 x x 17 20 x 17 brown creeper 2 1 x x 15 20 13 Bewick’s wren 1 2 1 x 15 house wren 1 1 x 15 10 x 6 winter wren 1 1 x 30 golden-crowned kinglet 2 western bluebird 1 1 1 1 x 15 10 x Townsend’s solitaire 1 1 2 Swainson’s thrush 2 2 1 2 7 hermit thrush 1 1 2 American robin 1 1 1 1 x 5 varied thrush 1 1 2 wrentit 1 1 x

2 Species use of oak habitat 3 The 50 most frequent bird species observed in 9 oak woodland sites in the Willamette Valley, Oregon, 1994-1996. Numbers refer to ranking in abundance (1-50).

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

69 Brown

Habitats

Species Dry hillside/ grass forb Deciduois- hardwood Conifer- forest hardwood Shrub-forest edge Grass-forest edge cedar waxwing 2 2 19 European starling 1 2 1 1 15 10 12 solitary vireo 1 1 20 Hutton’s vireo 1 2 1 x 35 warbling vireo 1 2 1 x 42 orange-crowned warbler 1 1 1 x 3 Nashville warbler 1 1 1 yellow-rumped warbler 1 1 2 black-throated gray warbler 1 1 1 x MacGillivray’s warbler 2 1 40 Wilson’s warbler 1 1 27 yellow-breasted chat 2 2 western tananger 2 1 1 2 x (?) 16 black-headed grosbeak 1 1 1 1 x lazuli bunting 1 2 x 29 rufous-sided towhee 1 1 1

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only used old-growth, no score was given.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

70 black-headed grosbeak black-headed tananger western yellow-breasted chat yellow-breasted rufous-sided towhee rufous-sided bunting lazuli Wilson’swarbler MacGillivray’swarbler warblergray black-throated warbler yellow-rumped Nashville warbler Nashville orange-crowned warblerorange-crowned warbling vireo warbling Hutton’s vireo Hutton’s vireo solitary starling European waxwing cedar

1 2 2 1 1 1 1 1 1 1 1 1 2 1 1 1 2 1 2 1 1 1 1 2 2 1 2 2 1 1 2 1 1 1 1 1 1 1 1 1 1 1 2 2 1 1994-1996. Numbers refer to ranking in abundance (1-50). abundance in ranking to refer 1994-1996.Numbers 3 2 1985

The 50 most frequent bird species observed in 9 oak woodland sites in the Willamettein sites Valley,woodland oak 9 in observed species bird frequent Oregon,most 50 The habitat oak of use Species AK OODLAND RESOURCES IN BLM’S EUGENE DISTRICT C I R T S I D E N E G U E S ’ M L B N I S E C R U O S E R D N A L D O WO K OA F O T N E M S S E S S A

1

Grass-forb hills

Deciduous- Snags

hardwoods

Coniferous

hardwoods 71

15 Suggested dbh

(inches) Cavities

10 Minimum tree

height (feet 1995 Csuti et al. et x (?) x x x x x x x

Oak

2 1977 Hagar Stern and 16 27 29 40 42 35 20 19 12 3

Top 50 birds

3 Brown

Habitats

Species Dry hillside/ grass forb Deciduois- hardwood Conifer- forest hardwood Shrub-forest edge Grass-forest edge brown towhee 1 chipping sparrow 1 1 1 1 vesper sparrow 1 1 lark sparrow 1 1 2 savannah sparrow 2 2 fox sparrow 1 1 1 2 song sparrow 1 1 2 2 21 white-crowned sparrow 1 2 2 2 25 dark-eyed junco 2 1 1 1 8 western meadowlark 1 2 Brewer’s blackbird 1 1 1 brown-headed cowbird 1 1 1 1 11 northern oriole 1 1 1 x 26 purple finch 1 1 1 1 10 house finch 1 2 1 1 x x 15 10 pine siskin 2 2 1 1

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only used old-growth, no score was given.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

72 house finch house finch purple oriole northern cowbird brown-headed pine siskin pine blackbird Brewer’s western meadowlark western dark-eyed junco dark-eyed white-crowned sparrow white-crowned sparrow song sparrow fox savannahsparrow lark sparrow lark vesper sparrow vesper sparrow chipping brown towhee brown 1 1 2 1 1

1 1 1 1 2 1 2 2 2 1 1 2 1 1 1 1 2 1 1 2 1 1 2 1 1 1 1 1 1 1 1 1 1 2 2 1 2 1 1 1 1 1 1 1 2 2 1 1994-1996. Numbers refer to ranking in abundance (1-50). abundance in ranking to refer 1994-1996.Numbers 3 2 1985

The 50 most frequent bird species observed in 9 oak woodland sites in the Willamettein sites Valley,woodland oak 9 in observed species bird frequent Oregon,most 50 The habitat oak of use Species AK OODLAND RESOURCES IN BLM’S EUGENE DISTRICT C I R T S I D E N E G U E S ’ M L B N I S E C R U O S E R D N A L D O WO K OA F O T N E M S S E S S A

1

Grass-forb hills Snags

x Deciduous-

hardwoods

Coniferous x

hardwoods 15 73 Suggested dbh

(inches) Cavities

10 Minimum tree

height (feet 1995 Csuti et al. et x

Oak

2 1977 Hagar Stern and 26 10 11 25 21 8

Top 50 birds

3 Brown

Habitats

Species Dry hillside/ grass forb Deciduois- hardwood Conifer- forest hardwood Shrub-forest edge Grass-forest edge lesser goldfinch 1 2 1 x American goldfinch 1 2 1 14 evening grosbeak 2 47 Virginia opossum 1 2 x x 25 10 vagrant shrew 2 2 1 1 Trowbridge’s shrew 2 shrew-mole 1 coast mole 1 2 2 Townsend’s mole 2 2 1 big brown bat 2 2 x x 17 20 silver-haired bat 2 x x 17 20 hoary bat 2 California myotis 2 x 17 10 long-eared myotis 2 x x 17 10 little brown myotis 2 2 x x 17 10 fringed myotis 2 2 x x 17 10

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only used old-growth, no score was given.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

74 Virginia opossum Virginia grosbeak evening big brown bat brown big Townsend’smole mole coast shrew-mole Trowbridge’sshrew vagrantshrew goldfinch American goldfinch lesser silver-hairedbat California myotis California bat hoary long-eared myotis long-eared little brown myotis brown little fringed myotis fringed

1 2 2 1 1 2 2 2 2 2 2 1 1 2 2 2 2 2 2 2 2 2 2 2 2 1 1 1 1 2 1 1994-1996. Numbers refer to ranking in abundance (1-50). abundance in ranking to refer 1994-1996.Numbers 3 2 1985

The 50 most frequent bird species observed in 9 oak woodland sites in the Willamettein sites Valley,woodland oak 9 in observed species bird frequent Oregon,most 50 The habitat oak of use Species AK OODLAND RESOURCES IN BLM’S EUGENE DISTRICT C I R T S I D E N E G U E S ’ M L B N I S E C R U O S E R D N A L D O WO K OA F O T N E M S S E S S A

1

Grass-forb hills Snags x x x x x x Deciduous-

hardwoods

Coniferous x x x x x x x

hardwoods 75 25 17 17 17 17 17 17 Suggested dbh

(inches) Cavities 10 20 20 10 10 10 10 Minimum tree

height (feet 1995 Csuti et al. et x

Oak

2 1977 Hagar Stern and 47 14

Top 50 birds

3 Brown

Habitats

Species Dry hillside/ grass forb Deciduois- hardwood Conifer- forest hardwood Shrub-forest edge Grass-forest edge long-legged myotis 1 1 x x 17 10 x Yuma myotis 2 1 x x 17 10 x pallid bat x 17 20 x coyote 1 1 1 2 1 gray fox 1 1 x x 29 10 x red fox 1 1 1 1 black bear 2 2 29 10 raccoon 2 1 1 x x x 25 10 striped skunk 1 2 2 2 long-tailed weasel 1 2 2 2 2 x x x 17 10 ermine 2 1 x x 15 10 mink 2 2 2 spotted skunk 1 1 2 2 x x 25 10 mountain lion 2 2 bobcat 2 2 2 2 x x 29 10 elk 1 1 1 1

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only used old-growth, no score was given.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

76 long-legged myotis long-legged Yumamyotis pallid bat pallid gray fox gray coyote ermine weasel long-tailed skunk striped raccoon bear black spotted skunk spotted mink fox red bobcat lion mountain elk 1 1 2 2 1

1 2 1 1 2 2 1 1 2 1 2 1 2 2 1 1 1 1 1 1 2 2 1 2 1 2 1 2 2 1 2 2 2 2 1 2 1 1 2 2 2 2 1 1994-1996. Numbers refer to ranking in abundance (1-50). abundance in ranking to refer 1994-1996.Numbers 3 2 1985

The 50 most frequent bird species observed in 9 oak woodland sites in the Willamettein sites Valley,woodland oak 9 in observed species bird frequent Oregon,most 50 The habitat oak of use Species AK OODLAND RESOURCES IN BLM’S EUGENE DISTRICT C I R T S I D E N E G U E S ’ M L B N I S E C R U O S E R D N A L D O WO K OA F O T N E M S S E S S A

1 x x

Grass-forb hills

Deciduous- Snags x x x x x x x x x

hardwoods

Coniferous x x x x x x x x

hardwoods

77 Suggested dbh 17 17 17 25 29 17 29 15 25 29

(inches) Cavities 10 10 20 10 10 10 10 10 10 10 Minimum tree

height (feet 1995 Csuti et al. et x x x x

Oak

2 1977 Hagar Stern and

Top 50 birds

3 Brown

Habitats

Species Dry hillside/ grass forb Deciduois- hardwood Conifer- forest hardwood Shrub-forest edge Grass-forest edge mule deer 1 1 1 1 mountain beaver 2 1 1 western gray squirrel 1 1 1 2 x x 17 20 x California ground squirrel 1 2 2 2 x Townsend’s chipmunk 1 2 2 2 Douglas’ squirrel 2 2 2 x 17 20 Botta’s pocket gopher 1 Camas pocket gopher 1 2 2 1 western pocket gopher 1 2 2 1 bushy-tailed woodrat 2 2 2 x x 17 10 dusky-footed woodrat 1 1 2 deer mouse 2 1 1 1 2 x x x 15 10 western harvest mouse 1 white-footed vole 2 California vole 1 1 gray-tailed vole 2 2

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only used old-growth, no score was given.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

78 gray-tailed vole gray-tailed western gray squirrel gray western beaver mountain deer mule California vole California white-footed vole white-footed western harvest mouse harvest western mouse deer squirrel ground California dusky-footed woodrat dusky-footed woodrat bushy-tailed gopher pocket western gopher pocket Camas squirrel Douglas’ Townsend’schipmunk Botta’s pocket gopher pocket Botta’s 1 1 2 1 1

2 1 1 1 2 1 2 1 2 1 1 1 1 2 1 1 2 1 2 2 2 2 2 1 1 1 1 2 2 2 2 2 2 2 2 1 1 2 2 1 1 2 2 1994-1996. Numbers refer to ranking in abundance (1-50). abundance in ranking to refer 1994-1996.Numbers 3 2 1985

The 50 most frequent bird species observed in 9 oak woodland sites in the Willamettein sites Valley,woodland oak 9 in observed species bird frequent Oregon,most 50 The habitat oak of use Species AK OODLAND RESOURCES IN BLM’S EUGENE DISTRICT C I R T S I D E N E G U E S ’ M L B N I S E C R U O S E R D N A L D O WO K OA F O T N E M S S E S S A

1 x

Grass-forb hills

Deciduous- Snags x x x

hardwoods

Coniferous x x x x

hardwoods

79 Suggested dbh 17 15 17 17

(inches) Cavities 20 10 10 20 Minimum tree

height (feet 1995 Csuti et al. et x x

Oak

2 1977 Hagar Stern and

Top 50 birds

3 Brown

Habitats

Species Dry hillside/ grass forb Deciduois- hardwood Conifer- forest hardwood Shrub-forest edge Grass-forest edge long-tailed vole 2 2 2 creeping vole 1 1 1 Townsend’s vole 2 2 2 Pacific jumping mouse 1 1 porcupine 1 black-tailed jack rabbit 1 1 2 European rabbit 2 2 2 brush rabbit 1 1 2 2 eastern cottontail 1 2 2

1 Habitats: Information is for breeding use only. 1=primary habitat; 2=secondary habitat. Habitat was scored as primary if any of six stand conditions were listed as primary breeding habitat. If species only used old-growth, no score was given.

ASSESSMENT OF OAK WOODLAND RESOURCES IN BLM’S EUGENE DISTRICT

80 eastern cottontail eastern rabbit brush rabbit European rabbit jack black-tailed porcupine mouse Pacificjumping Townsend’svole vole creeping vole long-tailed 1

1 1 1 1 2 1 2 1 2 1 1 2 1 2 2 2 2 2 2 2 2 2 1 2 1994-1996. Numbers refer to ranking in abundance (1-50). abundance in ranking to refer 1994-1996.Numbers 3 2 1985

The 50 most frequent bird species observed in 9 oak woodland sites in the Willamettein sites Valley,woodland oak 9 in observed species bird frequent Oregon,most 50 The habitat oak of use Species AK OODLAND RESOURCES IN BLM’S EUGENE DISTRICT C I R T S I D E N E G U E S ’ M L B N I S E C R U O S E R D N A L D O WO K OA F O T N E M S S E S S A

1

Grass-forb hills

Deciduous- Snags

hardwoods

Coniferous

hardwoods

81 Suggested dbh

(inches) Cavities

Minimum tree

height (feet 1995 Csuti et al. et

Oak

2 1977 Hagar Stern and

Top 50 birds

3